xref: /dragonfly/usr.bin/netstat/if.c (revision 2038fb68)
1 /*
2  * Copyright (c) 1983, 1988, 1993
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 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  * @(#)if.c	8.3 (Berkeley) 4/28/95
34  * $FreeBSD: src/usr.bin/netstat/if.c,v 1.32.2.9 2001/09/17 14:35:46 ru Exp $
35  * $DragonFly: src/usr.bin/netstat/if.c,v 1.12 2008/03/07 11:34:21 sephe Exp $
36  */
37 
38 #include <sys/param.h>
39 #include <sys/protosw.h>
40 #include <sys/socket.h>
41 #include <sys/sysctl.h>
42 #include <sys/time.h>
43 
44 #include <net/if.h>
45 #include <net/if_var.h>
46 #include <net/if_dl.h>
47 #include <net/if_types.h>
48 #include <net/ethernet.h>
49 #include <netinet/in.h>
50 #include <netinet/in_var.h>
51 #include <netproto/ipx/ipx.h>
52 #include <netproto/ipx/ipx_if.h>
53 #ifdef NS
54 #include <netproto/ns/ns.h>
55 #include <netproto/ns/ns_if.h>
56 #endif
57 #ifdef ISO
58 #include <netiso/iso.h>
59 #include <netiso/iso_var.h>
60 #endif
61 #include <arpa/inet.h>
62 
63 #include <signal.h>
64 #include <stdio.h>
65 #include <stdlib.h>
66 #include <string.h>
67 #include <unistd.h>
68 
69 #include "netstat.h"
70 
71 #define	YES	1
72 #define	NO	0
73 
74 static void sidewaysintpr (u_int, u_long);
75 static void catchalarm (int);
76 
77 #ifdef INET6
78 char *netname6 (struct sockaddr_in6 *, struct in6_addr *);
79 static char ntop_buf[INET6_ADDRSTRLEN];		/* for inet_ntop() */
80 #endif
81 
82 
83 /*
84  * Display a formatted value, or a '-' in the same space.
85  */
86 static void
87 show_stat(const char *fmt, int width, u_long value, short showvalue)
88 {
89 	char newfmt[32];
90 
91 	/* Construct the format string */
92 	if (showvalue) {
93 		sprintf(newfmt, "%%%d%s", width, fmt);
94 		printf(newfmt, value);
95 	} else {
96 		sprintf(newfmt, "%%%ds", width);
97 		printf(newfmt, "-");
98 	}
99 }
100 
101 
102 
103 /*
104  * Print a description of the network interfaces.
105  */
106 void
107 intpr(int interval, u_long ifnetaddr, void (*pfunc)(char *))
108 {
109 	struct ifnet ifnet;
110 	struct ifaddr_container ifac;
111 	struct ifnethead ifnethead;
112 	union {
113 		struct ifaddr ifa;
114 		struct in_ifaddr in;
115 #ifdef INET6
116 		struct in6_ifaddr in6;
117 #endif
118 		struct ipx_ifaddr ipx;
119 #ifdef NS
120 		struct ns_ifaddr ns;
121 #endif
122 #ifdef ISO
123 		struct iso_ifaddr iso;
124 #endif
125 	} ifaddr;
126 	u_long ifaddraddr;
127 	u_long ifaddrcont_addr;
128 	u_long ifaddrfound;
129 	u_long ifnetfound;
130 	u_long opackets;
131 	u_long ipackets;
132 	u_long obytes;
133 	u_long ibytes;
134 	u_long oerrors;
135 	u_long ierrors;
136 	u_long collisions;
137 	short timer;
138 	int drops;
139 	struct sockaddr *sa = NULL;
140 	char name[IFNAMSIZ];
141 	short network_layer;
142 	short link_layer;
143 
144 	if (ifnetaddr == 0) {
145 		printf("ifnet: symbol not defined\n");
146 		return;
147 	}
148 	if (interval) {
149 		sidewaysintpr((unsigned)interval, ifnetaddr);
150 		return;
151 	}
152 	if (kread(ifnetaddr, (char *)&ifnethead, sizeof ifnethead))
153 		return;
154 	ifnetaddr = (u_long)TAILQ_FIRST(&ifnethead);
155 	if (kread(ifnetaddr, (char *)&ifnet, sizeof ifnet))
156 		return;
157 
158 	if (!pfunc) {
159 		printf("%-7.7s %-5.5s %-13.13s %-15.15s %8.8s %5.5s",
160 		       "Name", "Mtu", "Network", "Address", "Ipkts", "Ierrs");
161 		if (bflag)
162 			printf(" %10.10s","Ibytes");
163 		printf(" %8.8s %5.5s", "Opkts", "Oerrs");
164 		if (bflag)
165 			printf(" %10.10s","Obytes");
166 		printf(" %5s", "Coll");
167 		if (tflag)
168 			printf(" %s", "Time");
169 		if (dflag)
170 			printf(" %s", "Drop");
171 		putchar('\n');
172 	}
173 	ifaddraddr = 0;
174 	while (ifnetaddr || ifaddraddr) {
175 		struct sockaddr_in *sin;
176 #ifdef INET6
177 		struct sockaddr_in6 *sin6;
178 #endif
179 		char *cp;
180 		int n, m;
181 
182 		network_layer = 0;
183 		link_layer = 0;
184 
185 		if (ifaddraddr == 0) {
186 			struct ifaddrhead head;
187 
188 			ifnetfound = ifnetaddr;
189 			if (kread(ifnetaddr, (char *)&ifnet, sizeof ifnet))
190 				return;
191 			strlcpy(name, ifnet.if_xname, sizeof(name));
192 			ifnetaddr = (u_long)TAILQ_NEXT(&ifnet, if_link);
193 			if (interface != 0 && (strcmp(name, interface) != 0))
194 				continue;
195 			cp = strchr(name, '\0');
196 
197 			if (pfunc) {
198 				(*pfunc)(name);
199 				continue;
200 			}
201 
202 			if ((ifnet.if_flags&IFF_UP) == 0)
203 				*cp++ = '*';
204 			*cp = '\0';
205 
206 			if (kread((u_long)ifnet.if_addrheads,
207 				  (char *)&head, sizeof(head)))
208 				return;
209 
210 			ifaddrcont_addr =
211 				(u_long)TAILQ_FIRST(&head);
212 			if (ifaddrcont_addr == 0) {
213 				ifaddraddr = 0;
214 			} else {
215 				if (kread(ifaddrcont_addr, (char *)&ifac,
216 					  sizeof(ifac)))
217 					return;
218 				ifaddraddr = (u_long)ifac.ifa;
219 			}
220 		}
221 		ifaddrfound = ifaddraddr;
222 
223 		/*
224 		 * Get the interface stats.  These may get
225 		 * overriden below on a per-interface basis.
226 		 */
227 		opackets = ifnet.if_opackets;
228 		ipackets = ifnet.if_ipackets;
229 		obytes = ifnet.if_obytes;
230 		ibytes = ifnet.if_ibytes;
231 		oerrors = ifnet.if_oerrors;
232 		ierrors = ifnet.if_ierrors;
233 		collisions = ifnet.if_collisions;
234 		timer = ifnet.if_timer;
235 		drops = ifnet.if_snd.ifq_drops;
236 
237 		if (ifaddraddr == 0) {
238 			printf("%-7.7s %-5lu ", name, ifnet.if_mtu);
239 			printf("%-13.13s ", "none");
240 			printf("%-15.15s ", "none");
241 		} else {
242 			if (kread(ifaddraddr, (char *)&ifaddr, sizeof ifaddr)) {
243 				ifaddraddr = 0;
244 				continue;
245 			}
246 #define CP(x) ((char *)(x))
247 			cp = (CP(ifaddr.ifa.ifa_addr) - CP(ifaddraddr)) +
248 				CP(&ifaddr);
249 			sa = (struct sockaddr *)cp;
250 			if (af != AF_UNSPEC && sa->sa_family != af) {
251 				ifaddrcont_addr =
252 					(u_long)TAILQ_NEXT(&ifac, ifa_link);
253 				if (ifaddrcont_addr == 0) {
254 					ifaddraddr = 0;
255 				} else {
256 					if (kread(ifaddrcont_addr,
257 					    (char *)&ifac, sizeof(ifac))) {
258 						ifaddraddr = 0;
259 						continue;
260 					}
261 					ifaddraddr = (u_long)ifac.ifa;
262 				}
263 				continue;
264 			}
265 			printf("%-7.7s %-5lu ", name, ifnet.if_mtu);
266 			switch (sa->sa_family) {
267 			case AF_UNSPEC:
268 				printf("%-13.13s ", "none");
269 				printf("%-15.15s ", "none");
270 				break;
271 			case AF_INET:
272 				sin = (struct sockaddr_in *)sa;
273 #ifdef notdef
274 				/* can't use inet_makeaddr because kernel
275 				 * keeps nets unshifted.
276 				 */
277 				in = inet_makeaddr(ifaddr.in.ia_subnet,
278 					INADDR_ANY);
279 				printf("%-13.13s ", netname(in.s_addr,
280 				    ifaddr.in.ia_subnetmask));
281 #else
282 				printf("%-13.13s ",
283 				    netname(htonl(ifaddr.in.ia_subnet),
284 				    ifaddr.in.ia_subnetmask));
285 #endif
286 				printf("%-15.15s ",
287 				    routename(sin->sin_addr.s_addr));
288 
289 				network_layer = 1;
290 				break;
291 #ifdef INET6
292 			case AF_INET6:
293 				sin6 = (struct sockaddr_in6 *)sa;
294 				printf("%-11.11s ",
295 				       netname6(&ifaddr.in6.ia_addr,
296 						&ifaddr.in6.ia_prefixmask.sin6_addr));
297 				printf("%-17.17s ",
298 				    (char *)inet_ntop(AF_INET6,
299 					&sin6->sin6_addr,
300 					ntop_buf, sizeof(ntop_buf)));
301 
302 				network_layer = 1;
303 				break;
304 #endif /*INET6*/
305 			case AF_IPX:
306 				{
307 				struct sockaddr_ipx *sipx =
308 					(struct sockaddr_ipx *)sa;
309 				u_long net;
310 				char netnum[10];
311 
312 				*(union ipx_net *) &net = sipx->sipx_addr.x_net;
313 				sprintf(netnum, "%lx", (u_long)ntohl(net));
314 				printf("ipx:%-8s  ", netnum);
315 /*				printf("ipx:%-8s ", netname(net, 0L)); */
316 				printf("%-15s ",
317 				    ipx_phost((struct sockaddr *)sipx));
318 				}
319 				break;
320 
321 			case AF_APPLETALK:
322 				printf("atalk:%-12.12s ",atalk_print(sa,0x10) );
323 				printf("%-9.9s  ",atalk_print(sa,0x0b) );
324 				break;
325 #ifdef NS
326 			case AF_NS:
327 				{
328 				struct sockaddr_ns *sns =
329 					(struct sockaddr_ns *)sa;
330 				u_long net;
331 				char netnum[10];
332 
333 				*(union ns_net *) &net = sns->sns_addr.x_net;
334 				sprintf(netnum, "%lxH", ntohl(net));
335 				upHex(netnum);
336 				printf("ns:%-8s ", netnum);
337 				printf("%-15s ",
338 				    ns_phost((struct sockaddr *)sns));
339 				}
340 				break;
341 #endif
342 			case AF_LINK:
343 				{
344 				struct sockaddr_dl *sdl =
345 					(struct sockaddr_dl *)sa;
346 				char linknum[10];
347 				cp = (char *)LLADDR(sdl);
348 				n = sdl->sdl_alen;
349 				sprintf(linknum, "<Link#%d>", sdl->sdl_index);
350 				m = printf("%-11.11s ", linknum);
351 				}
352 				goto hexprint;
353 			default:
354 				m = printf("(%d)", sa->sa_family);
355 				for (cp = sa->sa_len + (char *)sa;
356 					--cp > sa->sa_data && (*cp == 0);) {}
357 				n = cp - sa->sa_data + 1;
358 				cp = sa->sa_data;
359 			hexprint:
360 				while (--n >= 0)
361 					m += printf("%02x%c", *cp++ & 0xff,
362 						    n > 0 ? ':' : ' ');
363 				m = 30 - m;
364 				while (m-- > 0)
365 					putchar(' ');
366 
367 				link_layer = 1;
368 				break;
369 			}
370 
371 			/*
372 			 * Fixup the statistics for interfaces that
373 			 * update stats for their network addresses
374 			 */
375 			if (network_layer) {
376 				opackets = ifaddr.in.ia_ifa.if_opackets;
377 				ipackets = ifaddr.in.ia_ifa.if_ipackets;
378 				obytes = ifaddr.in.ia_ifa.if_obytes;
379 				ibytes = ifaddr.in.ia_ifa.if_ibytes;
380 			}
381 
382 			ifaddrcont_addr =
383 				(u_long)TAILQ_NEXT(&ifac, ifa_link);
384 			if (ifaddrcont_addr == 0) {
385 				ifaddraddr = 0;
386 			} else {
387 				if (kread(ifaddrcont_addr,
388 				    (char *)&ifac, sizeof(ifac))) {
389 					ifaddraddr = 0;
390 				} else {
391 					ifaddraddr = (u_long)ifac.ifa;
392 				}
393 			}
394 		}
395 
396 		show_stat("lu", 8, ipackets, link_layer|network_layer);
397 		printf(" ");
398 		show_stat("lu", 5, ierrors, link_layer);
399 		printf(" ");
400 		if (bflag) {
401 			show_stat("lu", 10, ibytes, link_layer|network_layer);
402 			printf(" ");
403 		}
404 		show_stat("lu", 8, opackets, link_layer|network_layer);
405 		printf(" ");
406 		show_stat("lu", 5, oerrors, link_layer);
407 		printf(" ");
408 		if (bflag) {
409 			show_stat("lu", 10, obytes, link_layer|network_layer);
410 			printf(" ");
411 		}
412 		show_stat("lu", 5, collisions, link_layer);
413 		if (tflag) {
414 			printf(" ");
415 			show_stat("d", 3, timer, link_layer);
416 		}
417 		if (dflag) {
418 			printf(" ");
419 			show_stat("d", 3, drops, link_layer);
420 		}
421 		putchar('\n');
422 		if (aflag && ifaddrfound) {
423 			/*
424 			 * Print family's multicast addresses
425 			 */
426 			u_long multiaddr;
427 			struct ifmultiaddr ifma;
428 			union {
429 				struct sockaddr sa;
430 				struct sockaddr_in in;
431 #ifdef INET6
432 				struct sockaddr_in6 in6;
433 #endif /* INET6 */
434 				struct sockaddr_dl dl;
435 			} msa;
436 			const char *fmt;
437 
438 			for(multiaddr = (u_long)ifnet.if_multiaddrs.lh_first;
439 			    multiaddr;
440 			    multiaddr = (u_long)ifma.ifma_link.le_next) {
441 				if (kread(multiaddr, (char *)&ifma,
442 					  sizeof ifma))
443 					break;
444 				if (kread((u_long)ifma.ifma_addr, (char *)&msa,
445 					  sizeof msa))
446 					break;
447 				if (msa.sa.sa_family != sa->sa_family)
448 					continue;
449 
450 				fmt = 0;
451 				switch (msa.sa.sa_family) {
452 				case AF_INET:
453 					fmt = routename(msa.in.sin_addr.s_addr);
454 					break;
455 #ifdef INET6
456 				case AF_INET6:
457 					printf("%23s %-19.19s(refs: %d)\n", "",
458 					       inet_ntop(AF_INET6,
459 							 &msa.in6.sin6_addr,
460 							 ntop_buf,
461 							 sizeof(ntop_buf)),
462 					       ifma.ifma_refcount);
463 					break;
464 #endif /* INET6 */
465 				case AF_LINK:
466 					switch (msa.dl.sdl_type) {
467 					case IFT_ETHER:
468 					case IFT_FDDI:
469 						fmt = ether_ntoa(
470 							(struct ether_addr *)
471 							LLADDR(&msa.dl));
472 						break;
473 					}
474 					break;
475 				}
476 				if (fmt)
477 					printf("%23s %s\n", "", fmt);
478 			}
479 		}
480 	}
481 }
482 
483 struct	iftot {
484 	SLIST_ENTRY(iftot) chain;
485 	char	ift_name[IFNAMSIZ];	/* interface name */
486 	u_long	ift_ip;			/* input packets */
487 	u_long	ift_ie;			/* input errors */
488 	u_long	ift_op;			/* output packets */
489 	u_long	ift_oe;			/* output errors */
490 	u_long	ift_co;			/* collisions */
491 	u_int	ift_dr;			/* drops */
492 	u_long	ift_ib;			/* input bytes */
493 	u_long	ift_ob;			/* output bytes */
494 };
495 
496 u_char	signalled;			/* set if alarm goes off "early" */
497 
498 /*
499  * Print a running summary of interface statistics.
500  * Repeat display every interval seconds, showing statistics
501  * collected over that interval.  Assumes that interval is non-zero.
502  * First line printed at top of screen is always cumulative.
503  * XXX - should be rewritten to use ifmib(4).
504  */
505 static void
506 sidewaysintpr(unsigned interval, u_long off)
507 {
508 	struct ifnet ifnet;
509 	u_long firstifnet;
510 	struct ifnethead ifnethead;
511 	struct iftot *iftot, *ip, *ipn, *total, *sum, *interesting;
512 	int line;
513 	int oldmask, first;
514 	u_long interesting_off;
515 
516 	if (kread(off, (char *)&ifnethead, sizeof ifnethead))
517 		return;
518 	firstifnet = (u_long)TAILQ_FIRST(&ifnethead);
519 
520 	if ((iftot = malloc(sizeof(struct iftot))) == NULL) {
521 		printf("malloc failed\n");
522 		exit(1);
523 	}
524 	memset(iftot, 0, sizeof(struct iftot));
525 
526 	interesting = NULL;
527 	interesting_off = 0;
528 	for (off = firstifnet, ip = iftot; off;) {
529 		char name[IFNAMSIZ];
530 
531 		if (kread(off, (char *)&ifnet, sizeof ifnet))
532 			break;
533 		strlcpy(name, ifnet.if_xname, sizeof(name));
534 		if (interface && strcmp(name, interface) == 0) {
535 			interesting = ip;
536 			interesting_off = off;
537 		}
538 		snprintf(ip->ift_name, 16, "(%s)", name);
539 		if ((ipn = malloc(sizeof(struct iftot))) == NULL) {
540 			printf("malloc failed\n");
541 			exit(1);
542 		}
543 		memset(ipn, 0, sizeof(struct iftot));
544 		SLIST_NEXT(ip, chain) = ipn;
545 		ip = ipn;
546 		off = (u_long)TAILQ_NEXT(&ifnet, if_link);
547 	}
548 	if ((total = malloc(sizeof(struct iftot))) == NULL) {
549 		printf("malloc failed\n");
550 		exit(1);
551 	}
552 	memset(total, 0, sizeof(struct iftot));
553 	if ((sum = malloc(sizeof(struct iftot))) == NULL) {
554 		printf("malloc failed\n");
555 		exit(1);
556 	}
557 	memset(sum, 0, sizeof(struct iftot));
558 
559 
560 	(void)signal(SIGALRM, catchalarm);
561 	signalled = NO;
562 	(void)alarm(interval);
563 	first = 1;
564 banner:
565 	printf("%17s %14s %16s", "input",
566 	    interesting ? interesting->ift_name : "(Total)", "output");
567 	putchar('\n');
568 	printf("%10s %5s %10s %10s %5s %10s %5s",
569 	    "packets", "errs", "bytes", "packets", "errs", "bytes", "colls");
570 	if (dflag)
571 		printf(" %5.5s", "drops");
572 	putchar('\n');
573 	fflush(stdout);
574 	line = 0;
575 loop:
576 	if (interesting != NULL) {
577 		ip = interesting;
578 		if (kread(interesting_off, (char *)&ifnet, sizeof ifnet)) {
579 			printf("???\n");
580 			exit(1);
581 		};
582 		if (!first) {
583 			printf("%10lu %5lu %10lu %10lu %5lu %10lu %5lu",
584 				ifnet.if_ipackets - ip->ift_ip,
585 				ifnet.if_ierrors - ip->ift_ie,
586 				ifnet.if_ibytes - ip->ift_ib,
587 				ifnet.if_opackets - ip->ift_op,
588 				ifnet.if_oerrors - ip->ift_oe,
589 				ifnet.if_obytes - ip->ift_ob,
590 				ifnet.if_collisions - ip->ift_co);
591 			if (dflag)
592 				printf(" %5u", ifnet.if_snd.ifq_drops - ip->ift_dr);
593 		}
594 		ip->ift_ip = ifnet.if_ipackets;
595 		ip->ift_ie = ifnet.if_ierrors;
596 		ip->ift_ib = ifnet.if_ibytes;
597 		ip->ift_op = ifnet.if_opackets;
598 		ip->ift_oe = ifnet.if_oerrors;
599 		ip->ift_ob = ifnet.if_obytes;
600 		ip->ift_co = ifnet.if_collisions;
601 		ip->ift_dr = ifnet.if_snd.ifq_drops;
602 	} else {
603 		sum->ift_ip = 0;
604 		sum->ift_ie = 0;
605 		sum->ift_ib = 0;
606 		sum->ift_op = 0;
607 		sum->ift_oe = 0;
608 		sum->ift_ob = 0;
609 		sum->ift_co = 0;
610 		sum->ift_dr = 0;
611 		for (off = firstifnet, ip = iftot;
612 		     off && SLIST_NEXT(ip, chain) != NULL;
613 		     ip = SLIST_NEXT(ip, chain)) {
614 			if (kread(off, (char *)&ifnet, sizeof ifnet)) {
615 				off = 0;
616 				continue;
617 			}
618 			sum->ift_ip += ifnet.if_ipackets;
619 			sum->ift_ie += ifnet.if_ierrors;
620 			sum->ift_ib += ifnet.if_ibytes;
621 			sum->ift_op += ifnet.if_opackets;
622 			sum->ift_oe += ifnet.if_oerrors;
623 			sum->ift_ob += ifnet.if_obytes;
624 			sum->ift_co += ifnet.if_collisions;
625 			sum->ift_dr += ifnet.if_snd.ifq_drops;
626 			off = (u_long)TAILQ_NEXT(&ifnet, if_link);
627 		}
628 		if (!first) {
629 			printf("%10lu %5lu %10lu %10lu %5lu %10lu %5lu",
630 				sum->ift_ip - total->ift_ip,
631 				sum->ift_ie - total->ift_ie,
632 				sum->ift_ib - total->ift_ib,
633 				sum->ift_op - total->ift_op,
634 				sum->ift_oe - total->ift_oe,
635 				sum->ift_ob - total->ift_ob,
636 				sum->ift_co - total->ift_co);
637 			if (dflag)
638 				printf(" %5u", sum->ift_dr - total->ift_dr);
639 		}
640 		*total = *sum;
641 	}
642 	if (!first)
643 		putchar('\n');
644 	fflush(stdout);
645 	oldmask = sigblock(sigmask(SIGALRM));
646 	if (! signalled) {
647 		sigpause(0);
648 	}
649 	sigsetmask(oldmask);
650 	signalled = NO;
651 	(void)alarm(interval);
652 	line++;
653 	first = 0;
654 	if (line == 21)
655 		goto banner;
656 	else
657 		goto loop;
658 	/*NOTREACHED*/
659 }
660 
661 /*
662  * Called if an interval expires before sidewaysintpr has completed a loop.
663  * Sets a flag to not wait for the alarm.
664  */
665 static void
666 catchalarm(int signo __unused)
667 {
668 	signalled = YES;
669 }
670