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 1.12 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 ISO
  54 #include <netiso/iso.h>
  55 #include <netiso/iso_var.h>
  56 #endif
  57 #include <arpa/inet.h>
  58
  59 #include <signal.h>
  60 #include <stdio.h>
  61 #include <stdlib.h>
  62 #include <string.h>
  63 #include <unistd.h>
  64
  65 #include "netstat.h"
  66
  67 #define YES     1
  68 #define NO      0
  69
  70 static void sidewaysintpr (u_int, u_long);
  71 static void catchalarm (int);
  72
  73 #ifdef INET6
  74 static char ntop_buf[INET6_ADDRSTRLEN];         /* for inet_ntop() */
  75 #endif
  76
  77
  78 /*
  79  * Display a formatted value, or a '-' in the same space.
  80  */
  81 static void
  82 show_stat(const char *fmt, int width, u_long value, short showvalue)
  83 {
  84         char newfmt[32];
  85
  86         /* Construct the format string */
  87         if (showvalue) {
  88                 sprintf(newfmt, "%%%d%s", width, fmt);
  89                 printf(newfmt, value);
  90         } else {
  91                 sprintf(newfmt, "%%%ds", width);
  92                 printf(newfmt, "-");
  93         }
  94 }
  95
  96
  97
  98 /*
  99  * Print a description of the network interfaces.
 100  */
 101 void
 102 intpr(int interval1, u_long ifnetaddr, void (*pfunc)(char *))
 103 {
 104         struct ifnet ifnet;
 105         struct ifaddr_container ifac;
 106         struct ifnethead ifnethead;
 107         union {
 108                 struct ifaddr ifa;
 109                 struct in_ifaddr in;
 110 #ifdef INET6
 111                 struct in6_ifaddr in6;
 112 #endif
 113                 struct ipx_ifaddr ipx;
 114 #ifdef ISO
 115                 struct iso_ifaddr iso;
 116 #endif
 117         } ifaddr;
 118         u_long ifaddraddr;
 119         u_long ifaddrcont_addr;
 120         u_long ifaddrfound;
 121         u_long ifnetfound;
 122         u_long opackets;
 123         u_long ipackets;
 124         u_long obytes;
 125         u_long ibytes;
 126         u_long oerrors;
 127         u_long ierrors;
 128         u_long collisions;
 129         short timer;
 130         int drops;
 131         struct sockaddr *sa = NULL;
 132         char name[IFNAMSIZ];
 133         short network_layer;
 134         short link_layer;
 135
 136         if (ifnetaddr == 0) {
 137                 printf("ifnet: symbol not defined\n");
 138                 return;
 139         }
 140         if (interval1) {
 141                 sidewaysintpr((unsigned)interval1, ifnetaddr);
 142                 return;
 143         }
 144         if (kread(ifnetaddr, (char *)&ifnethead, sizeof ifnethead))
 145                 return;
 146         ifnetaddr = (u_long)TAILQ_FIRST(&ifnethead);
 147         if (kread(ifnetaddr, (char *)&ifnet, sizeof ifnet))
 148                 return;
 149
 150         if (!pfunc) {
 151                 printf("%-7.7s %-5.5s %-13.13s %-15.15s %8.8s %5.5s",
 152                        "Name", "Mtu", "Network", "Address", "Ipkts", "Ierrs");
 153                 if (bflag)
 154                         printf(" %10.10s","Ibytes");
 155                 printf(" %8.8s %5.5s", "Opkts", "Oerrs");
 156                 if (bflag)
 157                         printf(" %10.10s","Obytes");
 158                 printf(" %5s", "Coll");
 159                 if (tflag)
 160                         printf(" %s", "Time");
 161                 if (dflag)
 162                         printf(" %s", "Drop");
 163                 putchar('\n');
 164         }
 165         ifaddraddr = 0;
 166         while (ifnetaddr || ifaddraddr) {
 167                 struct sockaddr_in *sin;
 168 #ifdef INET6
 169                 struct sockaddr_in6 *sin6;
 170 #endif
 171                 char *cp;
 172                 int n, m;
 173
 174                 network_layer = 0;
 175                 link_layer = 0;
 176
 177                 if (ifaddraddr == 0) {
 178                         struct ifaddrhead head;
 179
 180                         ifnetfound = ifnetaddr;
 181                         if (kread(ifnetaddr, (char *)&ifnet, sizeof ifnet))
 182                                 return;
 183                         strlcpy(name, ifnet.if_xname, sizeof(name));
 184                         ifnetaddr = (u_long)TAILQ_NEXT(&ifnet, if_link);
 185                         if (interface != 0 && (strcmp(name, interface) != 0))
 186                                 continue;
 187                         cp = strchr(name, '\0');
 188
 189                         if (pfunc) {
 190                                 (*pfunc)(name);
 191                                 continue;
 192                         }
 193
 194                         if ((ifnet.if_flags&IFF_UP) == 0)
 195                                 *cp++ = '*';
 196                         *cp = '\0';
 197
 198                         if (kread((u_long)ifnet.if_addrheads,
 199                                   (char *)&head, sizeof(head)))
 200                                 return;
 201
 202                         ifaddrcont_addr =
 203                                 (u_long)TAILQ_FIRST(&head);
 204                         if (ifaddrcont_addr == 0) {
 205                                 ifaddraddr = 0;
 206                         } else {
 207                                 if (kread(ifaddrcont_addr, (char *)&ifac,
 208                                           sizeof(ifac)))
 209                                         return;
 210                                 ifaddraddr = (u_long)ifac.ifa;
 211                         }
 212                 }
 213                 ifaddrfound = ifaddraddr;
 214
 215                 /*
 216                  * Get the interface stats.  These may get
 217                  * overriden below on a per-interface basis.
 218                  */
 219                 opackets = ifnet.if_opackets;
 220                 ipackets = ifnet.if_ipackets;
 221                 obytes = ifnet.if_obytes;
 222                 ibytes = ifnet.if_ibytes;
 223                 oerrors = ifnet.if_oerrors;
 224                 ierrors = ifnet.if_ierrors;
 225                 collisions = ifnet.if_collisions;
 226                 timer = ifnet.if_timer;
 227                 drops = ifnet.if_snd.ifq_drops;
 228
 229                 if (ifaddraddr == 0) {
 230                         printf("%-7.7s %-5lu ", name, ifnet.if_mtu);
 231                         printf("%-13.13s ", "none");
 232                         printf("%-15.15s ", "none");
 233                 } else {
 234                         if (kread(ifaddraddr, (char *)&ifaddr, sizeof ifaddr)) {
 235                                 ifaddraddr = 0;
 236                                 continue;
 237                         }
 238 #define CP(x) ((char *)(x))
 239                         cp = (CP(ifaddr.ifa.ifa_addr) - CP(ifaddraddr)) +
 240                                 CP(&ifaddr);
 241                         sa = (struct sockaddr *)cp;
 242                         if (af != AF_UNSPEC && sa->sa_family != af) {
 243                                 ifaddrcont_addr =
 244                                         (u_long)TAILQ_NEXT(&ifac, ifa_link);
 245                                 if (ifaddrcont_addr == 0) {
 246                                         ifaddraddr = 0;
 247                                 } else {
 248                                         if (kread(ifaddrcont_addr,
 249                                             (char *)&ifac, sizeof(ifac))) {
 250                                                 ifaddraddr = 0;
 251                                                 continue;
 252                                         }
 253                                         ifaddraddr = (u_long)ifac.ifa;
 254                                 }
 255                                 continue;
 256                         }
 257                         printf("%-7.7s %-5lu ", name, ifnet.if_mtu);
 258                         switch (sa->sa_family) {
 259                         case AF_UNSPEC:
 260                                 printf("%-13.13s ", "none");
 261                                 printf("%-15.15s ", "none");
 262                                 break;
 263                         case AF_INET:
 264                                 sin = (struct sockaddr_in *)sa;
 265 #ifdef notdef
 266                                 /* can't use inet_makeaddr because kernel
 267                                  * keeps nets unshifted.
 268                                  */
 269                                 in = inet_makeaddr(ifaddr.in.ia_subnet,
 270                                         INADDR_ANY);
 271                                 printf("%-13.13s ", netname(in.s_addr,
 272                                     ifaddr.in.ia_subnetmask));
 273 #else
 274                                 printf("%-13.13s ",
 275                                     netname(htonl(ifaddr.in.ia_subnet),
 276                                     ifaddr.in.ia_subnetmask));
 277 #endif
 278                                 printf("%-15.15s ",
 279                                     routename(sin->sin_addr.s_addr));
 280
 281                                 network_layer = 1;
 282                                 break;
 283 #ifdef INET6
 284                         case AF_INET6:
 285                                 sin6 = (struct sockaddr_in6 *)sa;
 286                                 printf("%-11.11s ",
 287                                        netname6(&ifaddr.in6.ia_addr,
 288                                                 &ifaddr.in6.ia_prefixmask.sin6_addr));
 289                                 printf("%-17.17s ",
 290                                     inet_ntop(AF_INET6,
 291                                         &sin6->sin6_addr,
 292                                         ntop_buf, sizeof(ntop_buf)));
 293
 294                                 network_layer = 1;
 295                                 break;
 296 #endif /*INET6*/
 297                         case AF_IPX:
 298                                 {
 299                                 struct sockaddr_ipx *sipx =
 300                                         (struct sockaddr_ipx *)sa;
 301                                 u_long net;
 302                                 char netnum[10];
 303
 304                                 *(union ipx_net *) &net = sipx->sipx_addr.x_net;
 305                                 sprintf(netnum, "%lx", (u_long)ntohl(net));
 306                                 printf("ipx:%-8s  ", netnum);
 307 /*                              printf("ipx:%-8s ", netname(net, 0L)); */
 308                                 printf("%-15s ",
 309                                     ipx_phost((struct sockaddr *)sipx));
 310                                 }
 311                                 break;
 312
 313                         case AF_APPLETALK:
 314                                 printf("atalk:%-12.12s ",atalk_print(sa,0x10) );
 315                                 printf("%-9.9s  ",atalk_print(sa,0x0b) );
 316                                 break;
 317                         case AF_LINK:
 318                                 {
 319                                 struct sockaddr_dl *sdl =
 320                                         (struct sockaddr_dl *)sa;
 321                                 char linknum[10];
 322                                 cp = (char *)LLADDR(sdl);
 323                                 n = sdl->sdl_alen;
 324                                 sprintf(linknum, "<Link#%d>", sdl->sdl_index);
 325                                 m = printf("%-11.11s ", linknum);
 326                                 }
 327                                 goto hexprint;
 328                         default:
 329                                 m = printf("(%d)", sa->sa_family);
 330                                 for (cp = sa->sa_len + (char *)sa;
 331                                         --cp > sa->sa_data && (*cp == 0);) {}
 332                                 n = cp - sa->sa_data + 1;
 333                                 cp = sa->sa_data;
 334                         hexprint:
 335                                 while (--n >= 0)
 336                                         m += printf("%02x%c", *cp++ & 0xff,
 337                                                     n > 0 ? ':' : ' ');
 338                                 m = 30 - m;
 339                                 while (m-- > 0)
 340                                         putchar(' ');
 341
 342                                 link_layer = 1;
 343                                 break;
 344                         }
 345
 346                         /*
 347                          * Fixup the statistics for interfaces that
 348                          * update stats for their network addresses
 349                          */
 350                         if (network_layer) {
 351                                 opackets = ifaddr.in.ia_ifa.if_opackets;
 352                                 ipackets = ifaddr.in.ia_ifa.if_ipackets;
 353                                 obytes = ifaddr.in.ia_ifa.if_obytes;
 354                                 ibytes = ifaddr.in.ia_ifa.if_ibytes;
 355                         }
 356
 357                         ifaddrcont_addr =
 358                                 (u_long)TAILQ_NEXT(&ifac, ifa_link);
 359                         if (ifaddrcont_addr == 0) {
 360                                 ifaddraddr = 0;
 361                         } else {
 362                                 if (kread(ifaddrcont_addr,
 363                                     (char *)&ifac, sizeof(ifac))) {
 364                                         ifaddraddr = 0;
 365                                 } else {
 366                                         ifaddraddr = (u_long)ifac.ifa;
 367                                 }
 368                         }
 369                 }
 370
 371                 show_stat("lu", 8, ipackets, link_layer|network_layer);
 372                 printf(" ");
 373                 show_stat("lu", 5, ierrors, link_layer);
 374                 printf(" ");
 375                 if (bflag) {
 376                         show_stat("lu", 10, ibytes, link_layer|network_layer);
 377                         printf(" ");
 378                 }
 379                 show_stat("lu", 8, opackets, link_layer|network_layer);
 380                 printf(" ");
 381                 show_stat("lu", 5, oerrors, link_layer);
 382                 printf(" ");
 383                 if (bflag) {
 384                         show_stat("lu", 10, obytes, link_layer|network_layer);
 385                         printf(" ");
 386                 }
 387                 show_stat("lu", 5, collisions, link_layer);
 388                 if (tflag) {
 389                         printf(" ");
 390                         show_stat("d", 3, timer, link_layer);
 391                 }
 392                 if (dflag) {
 393                         printf(" ");
 394                         show_stat("d", 3, drops, link_layer);
 395                 }
 396                 putchar('\n');
 397                 if (aflag && ifaddrfound) {
 398                         /*
 399                          * Print family's multicast addresses
 400                          */
 401                         struct ifmultiaddr *multiaddr;
 402                         struct ifmultiaddr ifma;
 403                         union {
 404                                 struct sockaddr sa;
 405                                 struct sockaddr_in in;
 406 #ifdef INET6
 407                                 struct sockaddr_in6 in6;
 408 #endif /* INET6 */
 409                                 struct sockaddr_dl dl;
 410                         } msa;
 411                         const char *fmt;
 412
 413                         TAILQ_FOREACH(multiaddr, &ifnet.if_multiaddrs, ifma_link) {
 414                                 if (kread((u_long)multiaddr, (char *)&ifma,
 415                                           sizeof ifma))
 416                                         break;
 417                                 multiaddr = &ifma;
 418                                 if (kread((u_long)ifma.ifma_addr, (char *)&msa,
 419                                           sizeof msa))
 420                                         break;
 421                                 if (msa.sa.sa_family != sa->sa_family)
 422                                         continue;
 423
 424                                 fmt = 0;
 425                                 switch (msa.sa.sa_family) {
 426                                 case AF_INET:
 427                                         fmt = routename(msa.in.sin_addr.s_addr);
 428                                         break;
 429 #ifdef INET6
 430                                 case AF_INET6:
 431                                         printf("%23s %-19.19s(refs: %d)\n", "",
 432                                                inet_ntop(AF_INET6,
 433                                                          &msa.in6.sin6_addr,
 434                                                          ntop_buf,
 435                                                          sizeof(ntop_buf)),
 436                                                ifma.ifma_refcount);
 437                                         break;
 438 #endif /* INET6 */
 439                                 case AF_LINK:
 440                                         switch (msa.dl.sdl_type) {
 441                                         case IFT_ETHER:
 442                                         case IFT_FDDI:
 443                                                 fmt = ether_ntoa(
 444                                                         (struct ether_addr *)
 445                                                         LLADDR(&msa.dl));
 446                                                 break;
 447                                         }
 448                                         break;
 449                                 }
 450                                 if (fmt)
 451                                         printf("%23s %s\n", "", fmt);
 452                         }
 453                 }
 454         }
 455 }
 456
 457 struct  iftot {
 458         SLIST_ENTRY(iftot) chain;
 459         char    ift_name[IFNAMSIZ];     /* interface name */
 460         u_long  ift_ip;                 /* input packets */
 461         u_long  ift_ie;                 /* input errors */
 462         u_long  ift_op;                 /* output packets */
 463         u_long  ift_oe;                 /* output errors */
 464         u_long  ift_co;                 /* collisions */
 465         u_int   ift_dr;                 /* drops */
 466         u_long  ift_ib;                 /* input bytes */
 467         u_long  ift_ob;                 /* output bytes */
 468 };
 469
 470 u_char  signalled;                      /* set if alarm goes off "early" */
 471
 472 /*
 473  * Print a running summary of interface statistics.
 474  * Repeat display every interval1 seconds, showing statistics
 475  * collected over that interval.  Assumes that interval1 is non-zero.
 476  * First line printed at top of screen is always cumulative.
 477  * XXX - should be rewritten to use ifmib(4).
 478  */
 479 static void
 480 sidewaysintpr(unsigned interval1, u_long off)
 481 {
 482         struct ifnet ifnet;
 483         u_long firstifnet;
 484         struct ifnethead ifnethead;
 485         struct iftot *iftot, *ip, *ipn, *total, *sum, *interesting;
 486         int line;
 487         int oldmask, first;
 488         u_long interesting_off;
 489
 490         if (kread(off, (char *)&ifnethead, sizeof ifnethead))
 491                 return;
 492         firstifnet = (u_long)TAILQ_FIRST(&ifnethead);
 493
 494         if ((iftot = malloc(sizeof(struct iftot))) == NULL) {
 495                 printf("malloc failed\n");
 496                 exit(1);
 497         }
 498         memset(iftot, 0, sizeof(struct iftot));
 499
 500         interesting = NULL;
 501         interesting_off = 0;
 502         for (off = firstifnet, ip = iftot; off;) {
 503                 char name[IFNAMSIZ];
 504
 505                 if (kread(off, (char *)&ifnet, sizeof ifnet))
 506                         break;
 507                 strlcpy(name, ifnet.if_xname, sizeof(name));
 508                 if (interface && strcmp(name, interface) == 0) {
 509                         interesting = ip;
 510                         interesting_off = off;
 511                 }
 512                 snprintf(ip->ift_name, 16, "(%s)", name);
 513                 if ((ipn = malloc(sizeof(struct iftot))) == NULL) {
 514                         printf("malloc failed\n");
 515                         exit(1);
 516                 }
 517                 memset(ipn, 0, sizeof(struct iftot));
 518                 SLIST_NEXT(ip, chain) = ipn;
 519                 ip = ipn;
 520                 off = (u_long)TAILQ_NEXT(&ifnet, if_link);
 521         }
 522         if ((total = malloc(sizeof(struct iftot))) == NULL) {
 523                 printf("malloc failed\n");
 524                 exit(1);
 525         }
 526         memset(total, 0, sizeof(struct iftot));
 527         if ((sum = malloc(sizeof(struct iftot))) == NULL) {
 528                 printf("malloc failed\n");
 529                 exit(1);
 530         }
 531         memset(sum, 0, sizeof(struct iftot));
 532
 533
 534         (void)signal(SIGALRM, catchalarm);
 535         signalled = NO;
 536         (void)alarm(interval1);
 537         first = 1;
 538 banner:
 539         printf("%17s %14s %16s", "input",
 540             interesting ? interesting->ift_name : "(Total)", "output");
 541         putchar('\n');
 542         printf("%10s %5s %10s %10s %5s %10s %5s",
 543             "packets", "errs", "bytes", "packets", "errs", "bytes", "colls");
 544         if (dflag)
 545                 printf(" %5.5s", "drops");
 546         putchar('\n');
 547         fflush(stdout);
 548         line = 0;
 549 loop:
 550         if (interesting != NULL) {
 551                 ip = interesting;
 552                 if (kread(interesting_off, (char *)&ifnet, sizeof ifnet)) {
 553                         printf("???\n");
 554                         exit(1);
 555                 };
 556                 if (!first) {
 557                         printf("%10lu %5lu %10lu %10lu %5lu %10lu %5lu",
 558                                 ifnet.if_ipackets - ip->ift_ip,
 559                                 ifnet.if_ierrors - ip->ift_ie,
 560                                 ifnet.if_ibytes - ip->ift_ib,
 561                                 ifnet.if_opackets - ip->ift_op,
 562                                 ifnet.if_oerrors - ip->ift_oe,
 563                                 ifnet.if_obytes - ip->ift_ob,
 564                                 ifnet.if_collisions - ip->ift_co);
 565                         if (dflag)
 566                                 printf(" %5u", ifnet.if_snd.ifq_drops - ip->ift_dr);
 567                 }
 568                 ip->ift_ip = ifnet.if_ipackets;
 569                 ip->ift_ie = ifnet.if_ierrors;
 570                 ip->ift_ib = ifnet.if_ibytes;
 571                 ip->ift_op = ifnet.if_opackets;
 572                 ip->ift_oe = ifnet.if_oerrors;
 573                 ip->ift_ob = ifnet.if_obytes;
 574                 ip->ift_co = ifnet.if_collisions;
 575                 ip->ift_dr = ifnet.if_snd.ifq_drops;
 576         } else {
 577                 sum->ift_ip = 0;
 578                 sum->ift_ie = 0;
 579                 sum->ift_ib = 0;
 580                 sum->ift_op = 0;
 581                 sum->ift_oe = 0;
 582                 sum->ift_ob = 0;
 583                 sum->ift_co = 0;
 584                 sum->ift_dr = 0;
 585                 for (off = firstifnet, ip = iftot;
 586                      off && SLIST_NEXT(ip, chain) != NULL;
 587                      ip = SLIST_NEXT(ip, chain)) {
 588                         if (kread(off, (char *)&ifnet, sizeof ifnet)) {
 589                                 off = 0;
 590                                 continue;
 591                         }
 592                         sum->ift_ip += ifnet.if_ipackets;
 593                         sum->ift_ie += ifnet.if_ierrors;
 594                         sum->ift_ib += ifnet.if_ibytes;
 595                         sum->ift_op += ifnet.if_opackets;
 596                         sum->ift_oe += ifnet.if_oerrors;
 597                         sum->ift_ob += ifnet.if_obytes;
 598                         sum->ift_co += ifnet.if_collisions;
 599                         sum->ift_dr += ifnet.if_snd.ifq_drops;
 600                         off = (u_long)TAILQ_NEXT(&ifnet, if_link);
 601                 }
 602                 if (!first) {
 603                         printf("%10lu %5lu %10lu %10lu %5lu %10lu %5lu",
 604                                 sum->ift_ip - total->ift_ip,
 605                                 sum->ift_ie - total->ift_ie,
 606                                 sum->ift_ib - total->ift_ib,
 607                                 sum->ift_op - total->ift_op,
 608                                 sum->ift_oe - total->ift_oe,
 609                                 sum->ift_ob - total->ift_ob,
 610                                 sum->ift_co - total->ift_co);
 611                         if (dflag)
 612                                 printf(" %5u", sum->ift_dr - total->ift_dr);
 613                 }
 614                 *total = *sum;
 615         }
 616         if (!first)
 617                 putchar('\n');
 618         fflush(stdout);
 619         oldmask = sigblock(sigmask(SIGALRM));
 620         if (! signalled) {
 621                 sigpause(0);
 622         }
 623         sigsetmask(oldmask);
 624         signalled = NO;
 625         (void)alarm(interval1);
 626         line++;
 627         first = 0;
 628         if (line == 21)
 629                 goto banner;
 630         else
 631                 goto loop;
 632         /*NOTREACHED*/
 633 }
 634
 635 /*
 636  * Called if an interval expires before sidewaysintpr has completed a loop.
 637  * Sets a flag to not wait for the alarm.
 638  */
 639 static void
 640 catchalarm(int signo __unused)
 641 {
 642         signalled = YES;
 643 }