xref: /freebsd/usr.bin/netstat/if.c (revision c17d43407fe04133a94055b0dbc7ea8965654a9f)
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 
34 #ifndef lint
35 /*
36 static char sccsid[] = "@(#)if.c	8.3 (Berkeley) 4/28/95";
37 */
38 static const char rcsid[] =
39   "$FreeBSD$";
40 #endif /* not lint */
41 
42 #include <sys/types.h>
43 #include <sys/protosw.h>
44 #include <sys/socket.h>
45 #include <sys/sysctl.h>
46 #include <sys/time.h>
47 
48 #include <net/if.h>
49 #include <net/if_var.h>
50 #include <net/if_dl.h>
51 #include <net/if_types.h>
52 #include <net/bridge.h>
53 #include <net/ethernet.h>
54 #include <netinet/in.h>
55 #include <netinet/in_var.h>
56 #include <netipx/ipx.h>
57 #include <netipx/ipx_if.h>
58 #ifdef NS
59 #include <netns/ns.h>
60 #include <netns/ns_if.h>
61 #endif
62 #ifdef ISO
63 #include <netiso/iso.h>
64 #include <netiso/iso_var.h>
65 #endif
66 #include <arpa/inet.h>
67 
68 #include <signal.h>
69 #include <stdio.h>
70 #include <stdlib.h>
71 #include <string.h>
72 #include <unistd.h>
73 
74 #include "netstat.h"
75 
76 #define	YES	1
77 #define	NO	0
78 
79 static void sidewaysintpr (u_int, u_long);
80 static void catchalarm (int);
81 
82 #ifdef INET6
83 char *netname6 (struct sockaddr_in6 *, struct in6_addr *);
84 static char ntop_buf[INET6_ADDRSTRLEN];		/* for inet_ntop() */
85 static int bdg_done;
86 #endif
87 
88 /* print bridge statistics */
89 void
90 bdg_stats(u_long dummy __unused, char *name, int af __unused)
91 {
92     int i;
93     size_t slen ;
94     struct bdg_stats s ;
95     int mib[4] ;
96 
97     slen = sizeof(s);
98 
99     mib[0] = CTL_NET ;
100     mib[1] = PF_LINK ;
101     mib[2] = IFT_ETHER ;
102     mib[3] = PF_BDG ;
103     if (sysctl(mib,4, &s,&slen,NULL,0)==-1)
104 	return ; /* no bridging */
105 #ifdef INET6
106     if (bdg_done != 0)
107 	return;
108     else
109 	bdg_done = 1;
110 #endif
111     printf("-- Bridging statistics (%s) --\n", name) ;
112     printf(
113 "Name          In      Out  Forward     Drop    Bcast    Mcast    Local  Unknown\n");
114     for (i = 0 ; i < 16 ; i++) {
115 	if (s.s[i].name[0])
116 	printf("%-6s %9ld%9ld%9ld%9ld%9ld%9ld%9ld%9ld\n",
117 	  s.s[i].name,
118 	  s.s[i].p_in[(int)BDG_IN],
119 	  s.s[i].p_in[(int)BDG_OUT],
120 	  s.s[i].p_in[(int)BDG_FORWARD],
121 	  s.s[i].p_in[(int)BDG_DROP],
122 	  s.s[i].p_in[(int)BDG_BCAST],
123 	  s.s[i].p_in[(int)BDG_MCAST],
124 	  s.s[i].p_in[(int)BDG_LOCAL],
125 	  s.s[i].p_in[(int)BDG_UNKNOWN] );
126     }
127 }
128 
129 
130 
131 
132 /*
133  * Display a formatted value, or a '-' in the same space.
134  */
135 static void
136 show_stat(const char *fmt, int width, u_long value, short showvalue)
137 {
138 	char newfmt[32];
139 
140 	/* Construct the format string */
141 	if (showvalue) {
142 		sprintf(newfmt, "%%%d%s", width, fmt);
143 		printf(newfmt, value);
144 	} else {
145 		sprintf(newfmt, "%%%ds", width);
146 		printf(newfmt, "-");
147 	}
148 }
149 
150 
151 
152 /*
153  * Print a description of the network interfaces.
154  */
155 void
156 intpr(int interval, u_long ifnetaddr, void (*pfunc)(char *))
157 {
158 	struct ifnet ifnet;
159 	struct ifnethead ifnethead;
160 	union {
161 		struct ifaddr ifa;
162 		struct in_ifaddr in;
163 #ifdef INET6
164 		struct in6_ifaddr in6;
165 #endif
166 		struct ipx_ifaddr ipx;
167 #ifdef NS
168 		struct ns_ifaddr ns;
169 #endif
170 #ifdef ISO
171 		struct iso_ifaddr iso;
172 #endif
173 	} ifaddr;
174 	u_long ifaddraddr;
175 	u_long ifaddrfound;
176 	u_long ifnetfound;
177 	u_long opackets;
178 	u_long ipackets;
179 	u_long obytes;
180 	u_long ibytes;
181 	u_long oerrors;
182 	u_long ierrors;
183 	u_long collisions;
184 	short timer;
185 	int drops;
186 	struct sockaddr *sa = NULL;
187 	char name[32], tname[16];
188 	short network_layer;
189 	short link_layer;
190 
191 	if (ifnetaddr == 0) {
192 		printf("ifnet: symbol not defined\n");
193 		return;
194 	}
195 	if (interval) {
196 		sidewaysintpr((unsigned)interval, ifnetaddr);
197 		return;
198 	}
199 	if (kread(ifnetaddr, (char *)&ifnethead, sizeof ifnethead))
200 		return;
201 	ifnetaddr = (u_long)TAILQ_FIRST(&ifnethead);
202 	if (kread(ifnetaddr, (char *)&ifnet, sizeof ifnet))
203 		return;
204 
205 	if (!pfunc) {
206 		printf("%-5.5s %5.5s %-13.13s %-17.17s %8.8s %5.5s",
207 		       "Name", "Mtu", "Network", "Address", "Ipkts", "Ierrs");
208 		if (bflag)
209 			printf(" %10.10s","Ibytes");
210 		printf(" %8.8s %5.5s", "Opkts", "Oerrs");
211 		if (bflag)
212 			printf(" %10.10s","Obytes");
213 		printf(" %5s", "Coll");
214 		if (tflag)
215 			printf(" %s", "Time");
216 		if (dflag)
217 			printf(" %s", "Drop");
218 		putchar('\n');
219 	}
220 	ifaddraddr = 0;
221 	while (ifnetaddr || ifaddraddr) {
222 		struct sockaddr_in *sin;
223 #ifdef INET6
224 		struct sockaddr_in6 *sin6;
225 #endif
226 		register char *cp;
227 		int n, m;
228 
229 		network_layer = 0;
230 		link_layer = 0;
231 
232 		if (ifaddraddr == 0) {
233 			ifnetfound = ifnetaddr;
234 			if (kread(ifnetaddr, (char *)&ifnet, sizeof ifnet) ||
235 			    kread((u_long)ifnet.if_name, tname, 16))
236 				return;
237 			tname[15] = '\0';
238 			ifnetaddr = (u_long)TAILQ_NEXT(&ifnet, if_link);
239 			snprintf(name, 32, "%s%d", tname, ifnet.if_unit);
240 			if (interface != 0 && (strcmp(name, interface) != 0))
241 				continue;
242 			cp = index(name, '\0');
243 
244 			if (pfunc) {
245 				(*pfunc)(name);
246 				continue;
247 			}
248 
249 			if ((ifnet.if_flags&IFF_UP) == 0)
250 				*cp++ = '*';
251 			*cp = '\0';
252 			ifaddraddr = (u_long)TAILQ_FIRST(&ifnet.if_addrhead);
253 		}
254 		ifaddrfound = ifaddraddr;
255 
256 		/*
257 		 * Get the interface stats.  These may get
258 		 * overriden below on a per-interface basis.
259 		 */
260 		opackets = ifnet.if_opackets;
261 		ipackets = ifnet.if_ipackets;
262 		obytes = ifnet.if_obytes;
263 		ibytes = ifnet.if_ibytes;
264 		oerrors = ifnet.if_oerrors;
265 		ierrors = ifnet.if_ierrors;
266 		collisions = ifnet.if_collisions;
267 		timer = ifnet.if_timer;
268 		drops = ifnet.if_snd.ifq_drops;
269 
270 		if (ifaddraddr == 0) {
271 			printf("%-5.5s %5lu ", name, ifnet.if_mtu);
272 			printf("%-13.13s ", "none");
273 			printf("%-17.17s ", "none");
274 		} else {
275 			if (kread(ifaddraddr, (char *)&ifaddr, sizeof ifaddr)) {
276 				ifaddraddr = 0;
277 				continue;
278 			}
279 #define CP(x) ((char *)(x))
280 			cp = (CP(ifaddr.ifa.ifa_addr) - CP(ifaddraddr)) +
281 				CP(&ifaddr);
282 			sa = (struct sockaddr *)cp;
283 			if (af != AF_UNSPEC && sa->sa_family != af) {
284 				ifaddraddr =
285 				    (u_long)TAILQ_NEXT(&ifaddr.ifa, ifa_link);
286 				continue;
287 			}
288 			printf("%-5.5s %5lu ", name, ifnet.if_mtu);
289 			switch (sa->sa_family) {
290 			case AF_UNSPEC:
291 				printf("%-13.13s ", "none");
292 				printf("%-15.15s ", "none");
293 				break;
294 			case AF_INET:
295 				sin = (struct sockaddr_in *)sa;
296 #ifdef notdef
297 				/* can't use inet_makeaddr because kernel
298 				 * keeps nets unshifted.
299 				 */
300 				in = inet_makeaddr(ifaddr.in.ia_subnet,
301 					INADDR_ANY);
302 				printf("%-13.13s ", netname(in.s_addr,
303 				    ifaddr.in.ia_subnetmask));
304 #else
305 				printf("%-13.13s ",
306 				    netname(htonl(ifaddr.in.ia_subnet),
307 				    ifaddr.in.ia_subnetmask));
308 #endif
309 				printf("%-17.17s ",
310 				    routename(sin->sin_addr.s_addr));
311 
312 				network_layer = 1;
313 				break;
314 #ifdef INET6
315 			case AF_INET6:
316 				sin6 = (struct sockaddr_in6 *)sa;
317 				printf("%-13.13s ",
318 				       netname6(&ifaddr.in6.ia_addr,
319 						&ifaddr.in6.ia_prefixmask.sin6_addr));
320 				printf("%-17.17s ",
321 				    (char *)inet_ntop(AF_INET6,
322 					&sin6->sin6_addr,
323 					ntop_buf, sizeof(ntop_buf)));
324 
325 				network_layer = 1;
326 				break;
327 #endif /*INET6*/
328 			case AF_IPX:
329 				{
330 				struct sockaddr_ipx *sipx =
331 					(struct sockaddr_ipx *)sa;
332 				u_long net;
333 				char netnum[10];
334 
335 				*(union ipx_net *) &net = sipx->sipx_addr.x_net;
336 				sprintf(netnum, "%lx", (u_long)ntohl(net));
337 				printf("ipx:%-8s  ", netnum);
338 /*				printf("ipx:%-8s ", netname(net, 0L)); */
339 				printf("%-17s ",
340 				    ipx_phost((struct sockaddr *)sipx));
341 				}
342 
343 				network_layer = 1;
344 				break;
345 
346 			case AF_APPLETALK:
347 				printf("atalk:%-12.12s ",atalk_print(sa,0x10) );
348 				printf("%-11.11s  ",atalk_print(sa,0x0b) );
349 				break;
350 #ifdef NS
351 			case AF_NS:
352 				{
353 				struct sockaddr_ns *sns =
354 					(struct sockaddr_ns *)sa;
355 				u_long net;
356 				char netnum[10];
357 
358 				*(union ns_net *) &net = sns->sns_addr.x_net;
359 				sprintf(netnum, "%lxH", ntohl(net));
360 				upHex(netnum);
361 				printf("ns:%-10s ", netnum);
362 				printf("%-17s ",
363 				    ns_phost((struct sockaddr *)sns));
364 				}
365 				break;
366 #endif
367 			case AF_LINK:
368 				{
369 				struct sockaddr_dl *sdl =
370 					(struct sockaddr_dl *)sa;
371 				char linknum[10];
372 				cp = (char *)LLADDR(sdl);
373 				n = sdl->sdl_alen;
374 				sprintf(linknum, "<Link#%d>", sdl->sdl_index);
375 				m = printf("%-13.13s ", linknum);
376 				}
377 				goto hexprint;
378 			default:
379 				m = printf("(%d)", sa->sa_family);
380 				for (cp = sa->sa_len + (char *)sa;
381 					--cp > sa->sa_data && (*cp == 0);) {}
382 				n = cp - sa->sa_data + 1;
383 				cp = sa->sa_data;
384 			hexprint:
385 				while (--n >= 0)
386 					m += printf("%02x%c", *cp++ & 0xff,
387 						    n > 0 ? ':' : ' ');
388 				m = 32 - m;
389 				while (m-- > 0)
390 					putchar(' ');
391 
392 				link_layer = 1;
393 				break;
394 			}
395 
396 			/*
397 			 * Fixup the statistics for interfaces that
398 			 * update stats for their network addresses
399 			 */
400 			if (network_layer) {
401 				opackets = ifaddr.in.ia_ifa.if_opackets;
402 				ipackets = ifaddr.in.ia_ifa.if_ipackets;
403 				obytes = ifaddr.in.ia_ifa.if_obytes;
404 				ibytes = ifaddr.in.ia_ifa.if_ibytes;
405 			}
406 
407 			ifaddraddr = (u_long)TAILQ_NEXT(&ifaddr.ifa, ifa_link);
408 		}
409 
410 		show_stat("lu", 8, ipackets, link_layer|network_layer);
411 		printf(" ");
412 		show_stat("lu", 5, ierrors, link_layer);
413 		printf(" ");
414 		if (bflag) {
415 			show_stat("lu", 10, ibytes, link_layer|network_layer);
416 			printf(" ");
417 		}
418 		show_stat("lu", 8, opackets, link_layer|network_layer);
419 		printf(" ");
420 		show_stat("lu", 5, oerrors, link_layer);
421 		printf(" ");
422 		if (bflag) {
423 			show_stat("lu", 10, obytes, link_layer|network_layer);
424 			printf(" ");
425 		}
426 		show_stat("lu", 5, collisions, link_layer);
427 		if (tflag) {
428 			printf(" ");
429 			show_stat("d", 3, timer, link_layer);
430 		}
431 		if (dflag) {
432 			printf(" ");
433 			show_stat("d", 3, drops, link_layer);
434 		}
435 		putchar('\n');
436 		if (aflag && ifaddrfound) {
437 			/*
438 			 * Print family's multicast addresses
439 			 */
440 			struct ifmultiaddr *multiaddr;
441 			struct ifmultiaddr ifma;
442 			union {
443 				struct sockaddr sa;
444 				struct sockaddr_in in;
445 #ifdef INET6
446 				struct sockaddr_in6 in6;
447 #endif /* INET6 */
448 				struct sockaddr_dl dl;
449 			} msa;
450 			const char *fmt;
451 
452 			TAILQ_FOREACH(multiaddr, &ifnet.if_multiaddrs, ifma_link) {
453 				if (kread((u_long)multiaddr, (char *)&ifma,
454 					  sizeof ifma))
455 					break;
456 				multiaddr = &ifma;
457 				if (kread((u_long)ifma.ifma_addr, (char *)&msa,
458 					  sizeof msa))
459 					break;
460 				if (msa.sa.sa_family != sa->sa_family)
461 					continue;
462 
463 				fmt = 0;
464 				switch (msa.sa.sa_family) {
465 				case AF_INET:
466 					fmt = routename(msa.in.sin_addr.s_addr);
467 					break;
468 #ifdef INET6
469 				case AF_INET6:
470 					printf("%23s %-19.19s(refs: %d)\n", "",
471 					       inet_ntop(AF_INET6,
472 							 &msa.in6.sin6_addr,
473 							 ntop_buf,
474 							 sizeof(ntop_buf)),
475 					       ifma.ifma_refcount);
476 					break;
477 #endif /* INET6 */
478 				case AF_LINK:
479 					switch (msa.dl.sdl_type) {
480 					case IFT_ETHER:
481 					case IFT_FDDI:
482 						fmt = ether_ntoa(
483 							(struct ether_addr *)
484 							LLADDR(&msa.dl));
485 						break;
486 					}
487 					break;
488 				}
489 				if (fmt)
490 					printf("%23s %s\n", "", fmt);
491 			}
492 		}
493 	}
494 }
495 
496 struct	iftot {
497 	SLIST_ENTRY(iftot) chain;
498 	char	ift_name[16];		/* interface name */
499 	u_long	ift_ip;			/* input packets */
500 	u_long	ift_ie;			/* input errors */
501 	u_long	ift_op;			/* output packets */
502 	u_long	ift_oe;			/* output errors */
503 	u_long	ift_co;			/* collisions */
504 	u_int	ift_dr;			/* drops */
505 	u_long	ift_ib;			/* input bytes */
506 	u_long	ift_ob;			/* output bytes */
507 };
508 
509 u_char	signalled;			/* set if alarm goes off "early" */
510 
511 /*
512  * Print a running summary of interface statistics.
513  * Repeat display every interval seconds, showing statistics
514  * collected over that interval.  Assumes that interval is non-zero.
515  * First line printed at top of screen is always cumulative.
516  * XXX - should be rewritten to use ifmib(4).
517  */
518 static void
519 sidewaysintpr(unsigned interval, u_long off)
520 {
521 	struct ifnet ifnet;
522 	u_long firstifnet;
523 	struct ifnethead ifnethead;
524 	struct iftot *iftot, *ip, *ipn, *total, *sum, *interesting;
525 	register int line;
526 	int oldmask, first;
527 	u_long interesting_off;
528 
529 	if (kread(off, (char *)&ifnethead, sizeof ifnethead))
530 		return;
531 	firstifnet = (u_long)TAILQ_FIRST(&ifnethead);
532 
533 	if ((iftot = malloc(sizeof(struct iftot))) == NULL) {
534 		printf("malloc failed\n");
535 		exit(1);
536 	}
537 	memset(iftot, 0, sizeof(struct iftot));
538 
539 	interesting = NULL;
540 	interesting_off = 0;
541 	for (off = firstifnet, ip = iftot; off;) {
542 		char name[16], tname[16];
543 
544 		if (kread(off, (char *)&ifnet, sizeof ifnet))
545 			break;
546 		if (kread((u_long)ifnet.if_name, tname, 16))
547 			break;
548 		tname[15] = '\0';
549 		snprintf(name, 16, "%s%d", tname, ifnet.if_unit);
550 		if (interface && strcmp(name, interface) == 0) {
551 			interesting = ip;
552 			interesting_off = off;
553 		}
554 		snprintf(ip->ift_name, 16, "(%s)", name);;
555 		if ((ipn = malloc(sizeof(struct iftot))) == NULL) {
556 			printf("malloc failed\n");
557 			exit(1);
558 		}
559 		memset(ipn, 0, sizeof(struct iftot));
560 		SLIST_NEXT(ip, chain) = ipn;
561 		ip = ipn;
562 		off = (u_long)TAILQ_NEXT(&ifnet, if_link);
563 	}
564 	if ((total = malloc(sizeof(struct iftot))) == NULL) {
565 		printf("malloc failed\n");
566 		exit(1);
567 	}
568 	memset(total, 0, sizeof(struct iftot));
569 	if ((sum = malloc(sizeof(struct iftot))) == NULL) {
570 		printf("malloc failed\n");
571 		exit(1);
572 	}
573 	memset(sum, 0, sizeof(struct iftot));
574 
575 
576 	(void)signal(SIGALRM, catchalarm);
577 	signalled = NO;
578 	(void)alarm(interval);
579 	first = 1;
580 banner:
581 	printf("%17s %14s %16s", "input",
582 	    interesting ? interesting->ift_name : "(Total)", "output");
583 	putchar('\n');
584 	printf("%10s %5s %10s %10s %5s %10s %5s",
585 	    "packets", "errs", "bytes", "packets", "errs", "bytes", "colls");
586 	if (dflag)
587 		printf(" %5.5s", "drops");
588 	putchar('\n');
589 	fflush(stdout);
590 	line = 0;
591 loop:
592 	if (interesting != NULL) {
593 		ip = interesting;
594 		if (kread(interesting_off, (char *)&ifnet, sizeof ifnet)) {
595 			printf("???\n");
596 			exit(1);
597 		};
598 		if (!first) {
599 			printf("%10lu %5lu %10lu %10lu %5lu %10lu %5lu",
600 				ifnet.if_ipackets - ip->ift_ip,
601 				ifnet.if_ierrors - ip->ift_ie,
602 				ifnet.if_ibytes - ip->ift_ib,
603 				ifnet.if_opackets - ip->ift_op,
604 				ifnet.if_oerrors - ip->ift_oe,
605 				ifnet.if_obytes - ip->ift_ob,
606 				ifnet.if_collisions - ip->ift_co);
607 			if (dflag)
608 				printf(" %5u", ifnet.if_snd.ifq_drops - ip->ift_dr);
609 		}
610 		ip->ift_ip = ifnet.if_ipackets;
611 		ip->ift_ie = ifnet.if_ierrors;
612 		ip->ift_ib = ifnet.if_ibytes;
613 		ip->ift_op = ifnet.if_opackets;
614 		ip->ift_oe = ifnet.if_oerrors;
615 		ip->ift_ob = ifnet.if_obytes;
616 		ip->ift_co = ifnet.if_collisions;
617 		ip->ift_dr = ifnet.if_snd.ifq_drops;
618 	} else {
619 		sum->ift_ip = 0;
620 		sum->ift_ie = 0;
621 		sum->ift_ib = 0;
622 		sum->ift_op = 0;
623 		sum->ift_oe = 0;
624 		sum->ift_ob = 0;
625 		sum->ift_co = 0;
626 		sum->ift_dr = 0;
627 		for (off = firstifnet, ip = iftot;
628 		     off && SLIST_NEXT(ip, chain) != NULL;
629 		     ip = SLIST_NEXT(ip, chain)) {
630 			if (kread(off, (char *)&ifnet, sizeof ifnet)) {
631 				off = 0;
632 				continue;
633 			}
634 			sum->ift_ip += ifnet.if_ipackets;
635 			sum->ift_ie += ifnet.if_ierrors;
636 			sum->ift_ib += ifnet.if_ibytes;
637 			sum->ift_op += ifnet.if_opackets;
638 			sum->ift_oe += ifnet.if_oerrors;
639 			sum->ift_ob += ifnet.if_obytes;
640 			sum->ift_co += ifnet.if_collisions;
641 			sum->ift_dr += ifnet.if_snd.ifq_drops;
642 			off = (u_long)TAILQ_NEXT(&ifnet, if_link);
643 		}
644 		if (!first) {
645 			printf("%10lu %5lu %10lu %10lu %5lu %10lu %5lu",
646 				sum->ift_ip - total->ift_ip,
647 				sum->ift_ie - total->ift_ie,
648 				sum->ift_ib - total->ift_ib,
649 				sum->ift_op - total->ift_op,
650 				sum->ift_oe - total->ift_oe,
651 				sum->ift_ob - total->ift_ob,
652 				sum->ift_co - total->ift_co);
653 			if (dflag)
654 				printf(" %5u", sum->ift_dr - total->ift_dr);
655 		}
656 		*total = *sum;
657 	}
658 	if (!first)
659 		putchar('\n');
660 	fflush(stdout);
661 	oldmask = sigblock(sigmask(SIGALRM));
662 	if (! signalled) {
663 		sigpause(0);
664 	}
665 	sigsetmask(oldmask);
666 	signalled = NO;
667 	(void)alarm(interval);
668 	line++;
669 	first = 0;
670 	if (line == 21)
671 		goto banner;
672 	else
673 		goto loop;
674 	/*NOTREACHED*/
675 }
676 
677 /*
678  * Called if an interval expires before sidewaysintpr has completed a loop.
679  * Sets a flag to not wait for the alarm.
680  */
681 static void
682 catchalarm(int signo __unused)
683 {
684 	signalled = YES;
685 }
686