usr.bin/netstat/if.c

   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 1.11 2006/08/03 16:40:48 swildner 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 ifnethead ifnethead;
 111         union {
 112                 struct ifaddr ifa;
 113                 struct in_ifaddr in;
 114 #ifdef INET6
 115                 struct in6_ifaddr in6;
 116 #endif
 117                 struct ipx_ifaddr ipx;
 118 #ifdef NS
 119                 struct ns_ifaddr ns;
 120 #endif
 121 #ifdef ISO
 122                 struct iso_ifaddr iso;
 123 #endif
 124         } ifaddr;
 125         u_long ifaddraddr;
 126         u_long ifaddrfound;
 127         u_long ifnetfound;
 128         u_long opackets;
 129         u_long ipackets;
 130         u_long obytes;
 131         u_long ibytes;
 132         u_long oerrors;
 133         u_long ierrors;
 134         u_long collisions;
 135         short timer;
 136         int drops;
 137         struct sockaddr *sa = NULL;
 138         char name[IFNAMSIZ];
 139         short network_layer;
 140         short link_layer;
 141
 142         if (ifnetaddr == 0) {
 143                 printf("ifnet: symbol not defined\n");
 144                 return;
 145         }
 146         if (interval) {
 147                 sidewaysintpr((unsigned)interval, ifnetaddr);
 148                 return;
 149         }
 150         if (kread(ifnetaddr, (char *)&ifnethead, sizeof ifnethead))
 151                 return;
 152         ifnetaddr = (u_long)TAILQ_FIRST(&ifnethead);
 153         if (kread(ifnetaddr, (char *)&ifnet, sizeof ifnet))
 154                 return;
 155
 156         if (!pfunc) {
 157                 printf("%-7.7s %-5.5s %-13.13s %-15.15s %8.8s %5.5s",
 158                        "Name", "Mtu", "Network", "Address", "Ipkts", "Ierrs");
 159                 if (bflag)
 160                         printf(" %10.10s","Ibytes");
 161                 printf(" %8.8s %5.5s", "Opkts", "Oerrs");
 162                 if (bflag)
 163                         printf(" %10.10s","Obytes");
 164                 printf(" %5s", "Coll");
 165                 if (tflag)
 166                         printf(" %s", "Time");
 167                 if (dflag)
 168                         printf(" %s", "Drop");
 169                 putchar('\n');
 170         }
 171         ifaddraddr = 0;
 172         while (ifnetaddr || ifaddraddr) {
 173                 struct sockaddr_in *sin;
 174 #ifdef INET6
 175                 struct sockaddr_in6 *sin6;
 176 #endif
 177                 char *cp;
 178                 int n, m;
 179
 180                 network_layer = 0;
 181                 link_layer = 0;
 182
 183                 if (ifaddraddr == 0) {
 184                         ifnetfound = ifnetaddr;
 185                         if (kread(ifnetaddr, (char *)&ifnet, sizeof ifnet))
 186                                 return;
 187                         strlcpy(name, ifnet.if_xname, sizeof(name));
 188                         ifnetaddr = (u_long)TAILQ_NEXT(&ifnet, if_link);
 189                         if (interface != 0 && (strcmp(name, interface) != 0))
 190                                 continue;
 191                         cp = strchr(name, '\0');
 192
 193                         if (pfunc) {
 194                                 (*pfunc)(name);
 195                                 continue;
 196                         }
 197
 198                         if ((ifnet.if_flags&IFF_UP) == 0)
 199                                 *cp++ = '*';
 200                         *cp = '\0';
 201                         ifaddraddr = (u_long)TAILQ_FIRST(&ifnet.if_addrhead);
 202                 }
 203                 ifaddrfound = ifaddraddr;
 204
 205                 /*
 206                  * Get the interface stats.  These may get
 207                  * overriden below on a per-interface basis.
 208                  */
 209                 opackets = ifnet.if_opackets;
 210                 ipackets = ifnet.if_ipackets;
 211                 obytes = ifnet.if_obytes;
 212                 ibytes = ifnet.if_ibytes;
 213                 oerrors = ifnet.if_oerrors;
 214                 ierrors = ifnet.if_ierrors;
 215                 collisions = ifnet.if_collisions;
 216                 timer = ifnet.if_timer;
 217                 drops = ifnet.if_snd.ifq_drops;
 218
 219                 if (ifaddraddr == 0) {
 220                         printf("%-7.7s %-5lu ", name, ifnet.if_mtu);
 221                         printf("%-13.13s ", "none");
 222                         printf("%-15.15s ", "none");
 223                 } else {
 224                         if (kread(ifaddraddr, (char *)&ifaddr, sizeof ifaddr)) {
 225                                 ifaddraddr = 0;
 226                                 continue;
 227                         }
 228 #define CP(x) ((char *)(x))
 229                         cp = (CP(ifaddr.ifa.ifa_addr) - CP(ifaddraddr)) +
 230                                 CP(&ifaddr);
 231                         sa = (struct sockaddr *)cp;
 232                         if (af != AF_UNSPEC && sa->sa_family != af) {
 233                                 ifaddraddr =
 234                                     (u_long)TAILQ_NEXT(&ifaddr.ifa, ifa_link);
 235                                 continue;
 236                         }
 237                         printf("%-7.7s %-5lu ", name, ifnet.if_mtu);
 238                         switch (sa->sa_family) {
 239                         case AF_UNSPEC:
 240                                 printf("%-13.13s ", "none");
 241                                 printf("%-15.15s ", "none");
 242                                 break;
 243                         case AF_INET:
 244                                 sin = (struct sockaddr_in *)sa;
 245 #ifdef notdef
 246                                 /* can't use inet_makeaddr because kernel
 247                                  * keeps nets unshifted.
 248                                  */
 249                                 in = inet_makeaddr(ifaddr.in.ia_subnet,
 250                                         INADDR_ANY);
 251                                 printf("%-13.13s ", netname(in.s_addr,
 252                                     ifaddr.in.ia_subnetmask));
 253 #else
 254                                 printf("%-13.13s ",
 255                                     netname(htonl(ifaddr.in.ia_subnet),
 256                                     ifaddr.in.ia_subnetmask));
 257 #endif
 258                                 printf("%-15.15s ",
 259                                     routename(sin->sin_addr.s_addr));
 260
 261                                 network_layer = 1;
 262                                 break;
 263 #ifdef INET6
 264                         case AF_INET6:
 265                                 sin6 = (struct sockaddr_in6 *)sa;
 266                                 printf("%-11.11s ",
 267                                        netname6(&ifaddr.in6.ia_addr,
 268                                                 &ifaddr.in6.ia_prefixmask.sin6_addr));
 269                                 printf("%-17.17s ",
 270                                     (char *)inet_ntop(AF_INET6,
 271                                         &sin6->sin6_addr,
 272                                         ntop_buf, sizeof(ntop_buf)));
 273
 274                                 network_layer = 1;
 275                                 break;
 276 #endif /*INET6*/
 277                         case AF_IPX:
 278                                 {
 279                                 struct sockaddr_ipx *sipx =
 280                                         (struct sockaddr_ipx *)sa;
 281                                 u_long net;
 282                                 char netnum[10];
 283
 284                                 *(union ipx_net *) &net = sipx->sipx_addr.x_net;
 285                                 sprintf(netnum, "%lx", (u_long)ntohl(net));
 286                                 printf("ipx:%-8s  ", netnum);
 287 /*                              printf("ipx:%-8s ", netname(net, 0L)); */
 288                                 printf("%-15s ",
 289                                     ipx_phost((struct sockaddr *)sipx));
 290                                 }
 291                                 break;
 292
 293                         case AF_APPLETALK:
 294                                 printf("atalk:%-12.12s ",atalk_print(sa,0x10) );
 295                                 printf("%-9.9s  ",atalk_print(sa,0x0b) );
 296                                 break;
 297 #ifdef NS
 298                         case AF_NS:
 299                                 {
 300                                 struct sockaddr_ns *sns =
 301                                         (struct sockaddr_ns *)sa;
 302                                 u_long net;
 303                                 char netnum[10];
 304
 305                                 *(union ns_net *) &net = sns->sns_addr.x_net;
 306                                 sprintf(netnum, "%lxH", ntohl(net));
 307                                 upHex(netnum);
 308                                 printf("ns:%-8s ", netnum);
 309                                 printf("%-15s ",
 310                                     ns_phost((struct sockaddr *)sns));
 311                                 }
 312                                 break;
 313 #endif
 314                         case AF_LINK:
 315                                 {
 316                                 struct sockaddr_dl *sdl =
 317                                         (struct sockaddr_dl *)sa;
 318                                 char linknum[10];
 319                                 cp = (char *)LLADDR(sdl);
 320                                 n = sdl->sdl_alen;
 321                                 sprintf(linknum, "<Link#%d>", sdl->sdl_index);
 322                                 m = printf("%-11.11s ", linknum);
 323                                 }
 324                                 goto hexprint;
 325                         default:
 326                                 m = printf("(%d)", sa->sa_family);
 327                                 for (cp = sa->sa_len + (char *)sa;
 328                                         --cp > sa->sa_data && (*cp == 0);) {}
 329                                 n = cp - sa->sa_data + 1;
 330                                 cp = sa->sa_data;
 331                         hexprint:
 332                                 while (--n >= 0)
 333                                         m += printf("%02x%c", *cp++ & 0xff,
 334                                                     n > 0 ? ':' : ' ');
 335                                 m = 30 - m;
 336                                 while (m-- > 0)
 337                                         putchar(' ');
 338
 339                                 link_layer = 1;
 340                                 break;
 341                         }
 342
 343                         /*
 344                          * Fixup the statistics for interfaces that
 345                          * update stats for their network addresses
 346                          */
 347                         if (network_layer) {
 348                                 opackets = ifaddr.in.ia_ifa.if_opackets;
 349                                 ipackets = ifaddr.in.ia_ifa.if_ipackets;
 350                                 obytes = ifaddr.in.ia_ifa.if_obytes;
 351                                 ibytes = ifaddr.in.ia_ifa.if_ibytes;
 352                         }
 353
 354                         ifaddraddr = (u_long)TAILQ_NEXT(&ifaddr.ifa, ifa_link);
 355                 }
 356
 357                 show_stat("lu", 8, ipackets, link_layer|network_layer);
 358                 printf(" ");
 359                 show_stat("lu", 5, ierrors, link_layer);
 360                 printf(" ");
 361                 if (bflag) {
 362                         show_stat("lu", 10, ibytes, link_layer|network_layer);
 363                         printf(" ");
 364                 }
 365                 show_stat("lu", 8, opackets, link_layer|network_layer);
 366                 printf(" ");
 367                 show_stat("lu", 5, oerrors, link_layer);
 368                 printf(" ");
 369                 if (bflag) {
 370                         show_stat("lu", 10, obytes, link_layer|network_layer);
 371                         printf(" ");
 372                 }
 373                 show_stat("lu", 5, collisions, link_layer);
 374                 if (tflag) {
 375                         printf(" ");
 376                         show_stat("d", 3, timer, link_layer);
 377                 }
 378                 if (dflag) {
 379                         printf(" ");
 380                         show_stat("d", 3, drops, link_layer);
 381                 }
 382                 putchar('\n');
 383                 if (aflag && ifaddrfound) {
 384                         /*
 385                          * Print family's multicast addresses
 386                          */
 387                         u_long multiaddr;
 388                         struct ifmultiaddr ifma;
 389                         union {
 390                                 struct sockaddr sa;
 391                                 struct sockaddr_in in;
 392 #ifdef INET6
 393                                 struct sockaddr_in6 in6;
 394 #endif /* INET6 */
 395                                 struct sockaddr_dl dl;
 396                         } msa;
 397                         const char *fmt;
 398
 399                         for(multiaddr = (u_long)ifnet.if_multiaddrs.lh_first;
 400                             multiaddr;
 401                             multiaddr = (u_long)ifma.ifma_link.le_next) {
 402                                 if (kread(multiaddr, (char *)&ifma,
 403                                           sizeof ifma))
 404                                         break;
 405                                 if (kread((u_long)ifma.ifma_addr, (char *)&msa,
 406                                           sizeof msa))
 407                                         break;
 408                                 if (msa.sa.sa_family != sa->sa_family)
 409                                         continue;
 410
 411                                 fmt = 0;
 412                                 switch (msa.sa.sa_family) {
 413                                 case AF_INET:
 414                                         fmt = routename(msa.in.sin_addr.s_addr);
 415                                         break;
 416 #ifdef INET6
 417                                 case AF_INET6:
 418                                         printf("%23s %-19.19s(refs: %d)\n", "",
 419                                                inet_ntop(AF_INET6,
 420                                                          &msa.in6.sin6_addr,
 421                                                          ntop_buf,
 422                                                          sizeof(ntop_buf)),
 423                                                ifma.ifma_refcount);
 424                                         break;
 425 #endif /* INET6 */
 426                                 case AF_LINK:
 427                                         switch (msa.dl.sdl_type) {
 428                                         case IFT_ETHER:
 429                                         case IFT_FDDI:
 430                                                 fmt = ether_ntoa(
 431                                                         (struct ether_addr *)
 432                                                         LLADDR(&msa.dl));
 433                                                 break;
 434                                         }
 435                                         break;
 436                                 }
 437                                 if (fmt)
 438                                         printf("%23s %s\n", "", fmt);
 439                         }
 440                 }
 441         }
 442 }
 443
 444 struct  iftot {
 445         SLIST_ENTRY(iftot) chain;
 446         char    ift_name[IFNAMSIZ];     /* interface name */
 447         u_long  ift_ip;                 /* input packets */
 448         u_long  ift_ie;                 /* input errors */
 449         u_long  ift_op;                 /* output packets */
 450         u_long  ift_oe;                 /* output errors */
 451         u_long  ift_co;                 /* collisions */
 452         u_int   ift_dr;                 /* drops */
 453         u_long  ift_ib;                 /* input bytes */
 454         u_long  ift_ob;                 /* output bytes */
 455 };
 456
 457 u_char  signalled;                      /* set if alarm goes off "early" */
 458
 459 /*
 460  * Print a running summary of interface statistics.
 461  * Repeat display every interval seconds, showing statistics
 462  * collected over that interval.  Assumes that interval is non-zero.
 463  * First line printed at top of screen is always cumulative.
 464  * XXX - should be rewritten to use ifmib(4).
 465  */
 466 static void
 467 sidewaysintpr(unsigned interval, u_long off)
 468 {
 469         struct ifnet ifnet;
 470         u_long firstifnet;
 471         struct ifnethead ifnethead;
 472         struct iftot *iftot, *ip, *ipn, *total, *sum, *interesting;
 473         int line;
 474         int oldmask, first;
 475         u_long interesting_off;
 476
 477         if (kread(off, (char *)&ifnethead, sizeof ifnethead))
 478                 return;
 479         firstifnet = (u_long)TAILQ_FIRST(&ifnethead);
 480
 481         if ((iftot = malloc(sizeof(struct iftot))) == NULL) {
 482                 printf("malloc failed\n");
 483                 exit(1);
 484         }
 485         memset(iftot, 0, sizeof(struct iftot));
 486
 487         interesting = NULL;
 488         interesting_off = 0;
 489         for (off = firstifnet, ip = iftot; off;) {
 490                 char name[IFNAMSIZ];
 491
 492                 if (kread(off, (char *)&ifnet, sizeof ifnet))
 493                         break;
 494                 strlcpy(name, ifnet.if_xname, sizeof(name));
 495                 if (interface && strcmp(name, interface) == 0) {
 496                         interesting = ip;
 497                         interesting_off = off;
 498                 }
 499                 snprintf(ip->ift_name, 16, "(%s)", name);
 500                 if ((ipn = malloc(sizeof(struct iftot))) == NULL) {
 501                         printf("malloc failed\n");
 502                         exit(1);
 503                 }
 504                 memset(ipn, 0, sizeof(struct iftot));
 505                 SLIST_NEXT(ip, chain) = ipn;
 506                 ip = ipn;
 507                 off = (u_long)TAILQ_NEXT(&ifnet, if_link);
 508         }
 509         if ((total = malloc(sizeof(struct iftot))) == NULL) {
 510                 printf("malloc failed\n");
 511                 exit(1);
 512         }
 513         memset(total, 0, sizeof(struct iftot));
 514         if ((sum = malloc(sizeof(struct iftot))) == NULL) {
 515                 printf("malloc failed\n");
 516                 exit(1);
 517         }
 518         memset(sum, 0, sizeof(struct iftot));
 519
 520
 521         (void)signal(SIGALRM, catchalarm);
 522         signalled = NO;
 523         (void)alarm(interval);
 524         first = 1;
 525 banner:
 526         printf("%17s %14s %16s", "input",
 527             interesting ? interesting->ift_name : "(Total)", "output");
 528         putchar('\n');
 529         printf("%10s %5s %10s %10s %5s %10s %5s",
 530             "packets", "errs", "bytes", "packets", "errs", "bytes", "colls");
 531         if (dflag)
 532                 printf(" %5.5s", "drops");
 533         putchar('\n');
 534         fflush(stdout);
 535         line = 0;
 536 loop:
 537         if (interesting != NULL) {
 538                 ip = interesting;
 539                 if (kread(interesting_off, (char *)&ifnet, sizeof ifnet)) {
 540                         printf("???\n");
 541                         exit(1);
 542                 };
 543                 if (!first) {
 544                         printf("%10lu %5lu %10lu %10lu %5lu %10lu %5lu",
 545                                 ifnet.if_ipackets - ip->ift_ip,
 546                                 ifnet.if_ierrors - ip->ift_ie,
 547                                 ifnet.if_ibytes - ip->ift_ib,
 548                                 ifnet.if_opackets - ip->ift_op,
 549                                 ifnet.if_oerrors - ip->ift_oe,
 550                                 ifnet.if_obytes - ip->ift_ob,
 551                                 ifnet.if_collisions - ip->ift_co);
 552                         if (dflag)
 553                                 printf(" %5u", ifnet.if_snd.ifq_drops - ip->ift_dr);
 554                 }
 555                 ip->ift_ip = ifnet.if_ipackets;
 556                 ip->ift_ie = ifnet.if_ierrors;
 557                 ip->ift_ib = ifnet.if_ibytes;
 558                 ip->ift_op = ifnet.if_opackets;
 559                 ip->ift_oe = ifnet.if_oerrors;
 560                 ip->ift_ob = ifnet.if_obytes;
 561                 ip->ift_co = ifnet.if_collisions;
 562                 ip->ift_dr = ifnet.if_snd.ifq_drops;
 563         } else {
 564                 sum->ift_ip = 0;
 565                 sum->ift_ie = 0;
 566                 sum->ift_ib = 0;
 567                 sum->ift_op = 0;
 568                 sum->ift_oe = 0;
 569                 sum->ift_ob = 0;
 570                 sum->ift_co = 0;
 571                 sum->ift_dr = 0;
 572                 for (off = firstifnet, ip = iftot;
 573                      off && SLIST_NEXT(ip, chain) != NULL;
 574                      ip = SLIST_NEXT(ip, chain)) {
 575                         if (kread(off, (char *)&ifnet, sizeof ifnet)) {
 576                                 off = 0;
 577                                 continue;
 578                         }
 579                         sum->ift_ip += ifnet.if_ipackets;
 580                         sum->ift_ie += ifnet.if_ierrors;
 581                         sum->ift_ib += ifnet.if_ibytes;
 582                         sum->ift_op += ifnet.if_opackets;
 583                         sum->ift_oe += ifnet.if_oerrors;
 584                         sum->ift_ob += ifnet.if_obytes;
 585                         sum->ift_co += ifnet.if_collisions;
 586                         sum->ift_dr += ifnet.if_snd.ifq_drops;
 587                         off = (u_long)TAILQ_NEXT(&ifnet, if_link);
 588                 }
 589                 if (!first) {
 590                         printf("%10lu %5lu %10lu %10lu %5lu %10lu %5lu",
 591                                 sum->ift_ip - total->ift_ip,
 592                                 sum->ift_ie - total->ift_ie,
 593                                 sum->ift_ib - total->ift_ib,
 594                                 sum->ift_op - total->ift_op,
 595                                 sum->ift_oe - total->ift_oe,
 596                                 sum->ift_ob - total->ift_ob,
 597                                 sum->ift_co - total->ift_co);
 598                         if (dflag)
 599                                 printf(" %5u", sum->ift_dr - total->ift_dr);
 600                 }
 601                 *total = *sum;
 602         }
 603         if (!first)
 604                 putchar('\n');
 605         fflush(stdout);
 606         oldmask = sigblock(sigmask(SIGALRM));
 607         if (! signalled) {
 608                 sigpause(0);
 609         }
 610         sigsetmask(oldmask);
 611         signalled = NO;
 612         (void)alarm(interval);
 613         line++;
 614         first = 0;
 615         if (line == 21)
 616                 goto banner;
 617         else
 618                 goto loop;
 619         /*NOTREACHED*/
 620 }
 621
 622 /*
 623  * Called if an interval expires before sidewaysintpr has completed a loop.
 624  * Sets a flag to not wait for the alarm.
 625  */
 626 static void
 627 catchalarm(int signo __unused)
 628 {
 629         signalled = YES;
 630 }