mDNSPosix/NetMonitor.c

   1 /* -*- Mode: C; tab-width: 4 -*-
   2  *
   3  * Copyright (c) 2002-2004 Apple Computer, Inc. All rights reserved.
   4  *
   5  * Licensed under the Apache License, Version 2.0 (the "License");
   6  * you may not use this file except in compliance with the License.
   7  * You may obtain a copy of the License at
   8  *
   9  *     http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  *
  17  */
  18
  19 //*************************************************************************************************************
  20 // Incorporate mDNS.c functionality
  21
  22 // We want to use much of the functionality provided by "mDNS.c",
  23 // except we'll steal the packets that would be sent to normal mDNSCoreReceive() routine
  24 #define mDNSCoreReceive __NOT__mDNSCoreReceive__NOT__
  25 #include "mDNS.c"
  26 #undef mDNSCoreReceive
  27
  28 //*************************************************************************************************************
  29 // Headers
  30
  31 #include <stdio.h>          // For printf()
  32 #include <stdlib.h>         // For malloc()
  33 #include <string.h>         // For strrchr(), strcmp()
  34 #include <time.h>           // For "struct tm" etc.
  35 #include <signal.h>         // For SIGINT, SIGTERM
  36 #if defined(WIN32)
  37 // Both mDNS.c and mDNSWin32.h declare UDPSocket_struct type resulting in a compile-time error, so
  38 // trick the compiler when including mDNSWin32.h
  39 #   define UDPSocket_struct _UDPSocket_struct
  40 #   include <mDNSEmbeddedAPI.h>
  41 #   include <mDNSWin32.h>
  42 #   include <PosixCompat.h>
  43 #   include <Poll.h>
  44 #   define IFNAMSIZ 256
  45 static HANDLE gStopEvent = INVALID_HANDLE_VALUE;
  46 static mDNSBool gRunning;
  47 static void CALLBACK StopNotification( HANDLE event, void *context ) { gRunning = mDNSfalse; }
  48 static BOOL WINAPI ConsoleControlHandler( DWORD inControlEvent ) { SetEvent( gStopEvent ); return TRUE; }
  49 void setlinebuf( FILE * fp ) {}
  50 #else
  51 #   include <netdb.h>           // For gethostbyname()
  52 #   include <sys/socket.h>      // For AF_INET, AF_INET6, etc.
  53 #   include <net/if.h>          // For IF_NAMESIZE
  54 #   include <netinet/in.h>      // For INADDR_NONE
  55 #   include <arpa/inet.h>       // For inet_addr()
  56 #   include "mDNSPosix.h"      // Defines the specific types needed to run mDNS on this platform
  57 #endif
  58 #include "ExampleClientApp.h"
  59
  60 //*************************************************************************************************************
  61 // Types and structures
  62
  63 enum
  64 {
  65     // Primitive operations
  66     OP_probe        = 0,
  67     OP_goodbye      = 1,
  68
  69     // These are meta-categories;
  70     // Query and Answer operations are actually subdivided into two classes:
  71     // Browse  query/answer and
  72     // Resolve query/answer
  73     OP_query        = 2,
  74     OP_answer       = 3,
  75
  76     // The "Browse" variants of query/answer
  77     OP_browsegroup  = 2,
  78     OP_browseq      = 2,
  79     OP_browsea      = 3,
  80
  81     // The "Resolve" variants of query/answer
  82     OP_resolvegroup = 4,
  83     OP_resolveq     = 4,
  84     OP_resolvea     = 5,
  85
  86     OP_NumTypes = 6
  87 };
  88
  89 typedef struct ActivityStat_struct ActivityStat;
  90 struct ActivityStat_struct
  91 {
  92     ActivityStat *next;
  93     domainname srvtype;
  94     int printed;
  95     int totalops;
  96     int stat[OP_NumTypes];
  97 };
  98
  99 typedef struct FilterList_struct FilterList;
 100 struct FilterList_struct
 101 {
 102     FilterList *next;
 103     mDNSAddr FilterAddr;
 104 };
 105
 106 //*************************************************************************************************************
 107 // Constants
 108
 109 #define kReportTopServices 15
 110 #define kReportTopHosts    15
 111
 112 //*************************************************************************************************************
 113 // Globals
 114
 115 mDNS mDNSStorage;                       // mDNS core uses this to store its globals
 116 static mDNS_PlatformSupport PlatformStorage;    // Stores this platform's globals
 117 mDNSexport const char ProgramName[] = "mDNSNetMonitor";
 118
 119 struct timeval tv_start, tv_end, tv_interval;
 120 static int FilterInterface = 0;
 121 static FilterList *Filters;
 122 #define ExactlyOneFilter (Filters && !Filters->next)
 123
 124 static int NumPktQ, NumPktL, NumPktR, NumPktB;  // Query/Legacy/Response/Bad
 125 static int NumProbes, NumGoodbyes, NumQuestions, NumLegacy, NumAnswers, NumAdditionals;
 126
 127 static ActivityStat *stats;
 128
 129 #define OPBanner "Total Ops   Probe   Goodbye  BrowseQ  BrowseA ResolveQ ResolveA"
 130
 131 //*************************************************************************************************************
 132 // Utilities
 133
 134 // Special version of printf that knows how to print IP addresses, DNS-format name strings, etc.
 135 mDNSlocal mDNSu32 mprintf(const char *format, ...) IS_A_PRINTF_STYLE_FUNCTION(1,2);
 136 mDNSlocal mDNSu32 mprintf(const char *format, ...)
 137 {
 138     mDNSu32 length;
 139     unsigned char buffer[512];
 140     va_list ptr;
 141     va_start(ptr,format);
 142     length = mDNS_vsnprintf((char *)buffer, sizeof(buffer), format, ptr);
 143     va_end(ptr);
 144     printf("%s", buffer);
 145     return(length);
 146 }
 147
 148 //*************************************************************************************************************
 149 // Host Address List
 150 //
 151 // Would benefit from a hash
 152
 153 typedef enum
 154 {
 155     HostPkt_Q        = 0,       // Query
 156     HostPkt_L        = 1,       // Legacy Query
 157     HostPkt_R        = 2,       // Response
 158     HostPkt_B        = 3,       // Bad
 159     HostPkt_NumTypes = 4
 160 } HostPkt_Type;
 161
 162 typedef struct
 163 {
 164     mDNSAddr addr;
 165     unsigned long pkts[HostPkt_NumTypes];
 166     unsigned long totalops;
 167     unsigned long stat[OP_NumTypes];
 168     domainname hostname;
 169     domainname revname;
 170     UTF8str255 HIHardware;
 171     UTF8str255 HISoftware;
 172     mDNSu32 NumQueries;
 173     mDNSs32 LastQuery;
 174 } HostEntry;
 175
 176 #define HostEntryTotalPackets(H) ((H)->pkts[HostPkt_Q] + (H)->pkts[HostPkt_L] + (H)->pkts[HostPkt_R] + (H)->pkts[HostPkt_B])
 177
 178 typedef struct
 179 {
 180     long num;
 181     long max;
 182     HostEntry   *hosts;
 183 } HostList;
 184
 185 static HostList IPv4HostList = { 0, 0, 0 };
 186 static HostList IPv6HostList = { 0, 0, 0 };
 187
 188 mDNSlocal HostEntry *FindHost(const mDNSAddr *addr, HostList *list)
 189 {
 190     long i;
 191
 192     for (i = 0; i < list->num; i++)
 193     {
 194         HostEntry *entry = list->hosts + i;
 195         if (mDNSSameAddress(addr, &entry->addr))
 196             return entry;
 197     }
 198
 199     return NULL;
 200 }
 201
 202 mDNSlocal HostEntry *AddHost(const mDNSAddr *addr, HostList *list)
 203 {
 204     int i;
 205     HostEntry *entry;
 206     if (list->num >= list->max)
 207     {
 208         long newMax = list->max + 64;
 209         HostEntry *newHosts = realloc(list->hosts, newMax * sizeof(HostEntry));
 210         if (newHosts == NULL)
 211             return NULL;
 212         list->max = newMax;
 213         list->hosts = newHosts;
 214     }
 215
 216     entry = list->hosts + list->num++;
 217
 218     entry->addr = *addr;
 219     for (i=0; i<HostPkt_NumTypes; i++) entry->pkts[i] = 0;
 220     entry->totalops = 0;
 221     for (i=0; i<OP_NumTypes;      i++) entry->stat[i] = 0;
 222     entry->hostname.c[0] = 0;
 223     entry->revname.c[0] = 0;
 224     entry->HIHardware.c[0] = 0;
 225     entry->HISoftware.c[0] = 0;
 226     entry->NumQueries = 0;
 227
 228     if (entry->addr.type == mDNSAddrType_IPv4)
 229     {
 230         mDNSv4Addr ip = entry->addr.ip.v4;
 231         char buffer[32];
 232         // Note: This is reverse order compared to a normal dotted-decimal IP address, so we can't use our customary "%.4a" format code
 233         mDNS_snprintf(buffer, sizeof(buffer), "%d.%d.%d.%d.in-addr.arpa.", ip.b[3], ip.b[2], ip.b[1], ip.b[0]);
 234         MakeDomainNameFromDNSNameString(&entry->revname, buffer);
 235     }
 236
 237     return(entry);
 238 }
 239
 240 mDNSlocal HostEntry *GotPacketFromHost(const mDNSAddr *addr, HostPkt_Type t, mDNSOpaque16 id)
 241 {
 242     if (ExactlyOneFilter) return(NULL);
 243     else
 244     {
 245         HostList *list = (addr->type == mDNSAddrType_IPv4) ? &IPv4HostList : &IPv6HostList;
 246         HostEntry *entry = FindHost(addr, list);
 247         if (!entry) entry = AddHost(addr, list);
 248         if (!entry) return(NULL);
 249         // Don't count our own interrogation packets
 250         if (id.NotAnInteger != 0xFFFF) entry->pkts[t]++;
 251         return(entry);
 252     }
 253 }
 254
 255 mDNSlocal void RecordHostInfo(HostEntry *entry, const ResourceRecord *const pktrr)
 256 {
 257     if (!entry->hostname.c[0])
 258     {
 259         if (pktrr->rrtype == kDNSType_A || pktrr->rrtype == kDNSType_AAAA)
 260         {
 261             // Should really check that the rdata in the address record matches the source address of this packet
 262             entry->NumQueries = 0;
 263             AssignDomainName(&entry->hostname, pktrr->name);
 264         }
 265
 266         if (pktrr->rrtype == kDNSType_PTR)
 267             if (SameDomainName(&entry->revname, pktrr->name))
 268             {
 269                 entry->NumQueries = 0;
 270                 AssignDomainName(&entry->hostname, &pktrr->rdata->u.name);
 271             }
 272     }
 273     else if (pktrr->rrtype == kDNSType_HINFO)
 274     {
 275         RDataBody *rd = &pktrr->rdata->u;
 276         mDNSu8 *rdend = (mDNSu8 *)rd + pktrr->rdlength;
 277         mDNSu8 *hw = rd->txt.c;
 278         mDNSu8 *sw = hw + 1 + (mDNSu32)hw[0];
 279         if (sw + 1 + sw[0] <= rdend)
 280         {
 281             AssignDomainName(&entry->hostname, pktrr->name);
 282             mDNSPlatformMemCopy(entry->HIHardware.c, hw, 1 + (mDNSu32)hw[0]);
 283             mDNSPlatformMemCopy(entry->HISoftware.c, sw, 1 + (mDNSu32)sw[0]);
 284         }
 285     }
 286 }
 287
 288 mDNSlocal void SendUnicastQuery(mDNS *const m, HostEntry *entry, domainname *name, mDNSu16 rrtype, mDNSInterfaceID InterfaceID)
 289 {
 290     const mDNSOpaque16 id = { { 0xFF, 0xFF } };
 291     DNSMessage query;
 292     mDNSu8       *qptr        = query.data;
 293     const mDNSu8 *const limit = query.data + sizeof(query.data);
 294     const mDNSAddr *target    = &entry->addr;
 295     InitializeDNSMessage(&query.h, id, QueryFlags);
 296     qptr = putQuestion(&query, qptr, limit, name, rrtype, kDNSClass_IN);
 297     entry->LastQuery = m->timenow;
 298     entry->NumQueries++;
 299
 300     // Note: When there are multiple mDNSResponder agents running on a single machine
 301     // (e.g. Apple mDNSResponder plus a SliMP3 server with embedded mDNSResponder)
 302     // it is possible that unicast queries may not go to the primary system responder.
 303     // We try the first query using unicast, but if that doesn't work we try again via multicast.
 304     if (entry->NumQueries > 2)
 305     {
 306         target = &AllDNSLinkGroup_v4;
 307     }
 308     else
 309     {
 310         //mprintf("%#a Q\n", target);
 311         InterfaceID = mDNSInterface_Any;    // Send query from our unicast reply socket
 312     }
 313
 314     mDNSSendDNSMessage(&mDNSStorage, &query, qptr, InterfaceID, mDNSNULL, target, MulticastDNSPort, mDNSNULL, mDNSNULL, mDNSfalse);
 315 }
 316
 317 mDNSlocal void AnalyseHost(mDNS *const m, HostEntry *entry, const mDNSInterfaceID InterfaceID)
 318 {
 319     // If we've done four queries without answer, give up
 320     if (entry->NumQueries >= 4) return;
 321
 322     // If we've done a query in the last second, give the host a chance to reply before trying again
 323     if (entry->NumQueries && m->timenow - entry->LastQuery < mDNSPlatformOneSecond) return;
 324
 325     // If we don't know the host name, try to find that first
 326     if (!entry->hostname.c[0])
 327     {
 328         if (entry->revname.c[0])
 329         {
 330             SendUnicastQuery(m, entry, &entry->revname, kDNSType_PTR, InterfaceID);
 331             //mprintf("%##s PTR %d\n", entry->revname.c, entry->NumQueries);
 332         }
 333     }
 334     // If we have the host name but no HINFO, now ask for that
 335     else if (!entry->HIHardware.c[0])
 336     {
 337         SendUnicastQuery(m, entry, &entry->hostname, kDNSType_HINFO, InterfaceID);
 338         //mprintf("%##s HINFO %d\n", entry->hostname.c, entry->NumQueries);
 339     }
 340 }
 341
 342 mDNSlocal int CompareHosts(const void *p1, const void *p2)
 343 {
 344     return (int)(HostEntryTotalPackets((HostEntry *)p2) - HostEntryTotalPackets((HostEntry *)p1));
 345 }
 346
 347 mDNSlocal void ShowSortedHostList(HostList *list, int max)
 348 {
 349     HostEntry *e, *end = &list->hosts[(max < list->num) ? max : list->num];
 350     qsort(list->hosts, list->num, sizeof(HostEntry), CompareHosts);
 351     if (list->num) mprintf("\n%-25s%s%s\n", "Source Address", OPBanner, "    Pkts    Query   LegacyQ Response");
 352     for (e = &list->hosts[0]; e < end; e++)
 353     {
 354         int len = mprintf("%#-25a", &e->addr);
 355         if (len > 25) mprintf("\n%25s", "");
 356         mprintf("%8lu %8lu %8lu %8lu %8lu %8lu %8lu", e->totalops,
 357                 e->stat[OP_probe], e->stat[OP_goodbye],
 358                 e->stat[OP_browseq], e->stat[OP_browsea],
 359                 e->stat[OP_resolveq], e->stat[OP_resolvea]);
 360         mprintf(" %8lu %8lu %8lu %8lu",
 361                 HostEntryTotalPackets(e), e->pkts[HostPkt_Q], e->pkts[HostPkt_L], e->pkts[HostPkt_R]);
 362         if (e->pkts[HostPkt_B]) mprintf("Bad: %8lu", e->pkts[HostPkt_B]);
 363         mprintf("\n");
 364         if (!e->HISoftware.c[0] && e->NumQueries > 2)
 365             mDNSPlatformMemCopy(&e->HISoftware, "\x27*** Unknown (Jaguar, Windows, etc.) ***", 0x28);
 366         if (e->hostname.c[0] || e->HIHardware.c[0] || e->HISoftware.c[0])
 367             mprintf("%##-45s %#-14s %#s\n", e->hostname.c, e->HIHardware.c, e->HISoftware.c);
 368     }
 369 }
 370
 371 //*************************************************************************************************************
 372 // Receive and process packets
 373
 374 mDNSexport mDNSBool ExtractServiceType(const domainname *const fqdn, domainname *const srvtype)
 375 {
 376     int i, len;
 377     const mDNSu8 *src = fqdn->c;
 378     mDNSu8 *dst = srvtype->c;
 379
 380     len = *src;
 381     if (len == 0 || len >= 0x40) return(mDNSfalse);
 382     if (src[1] != '_') src += 1 + len;
 383
 384     len = *src;
 385     if (len == 0 || len >= 0x40 || src[1] != '_') return(mDNSfalse);
 386     for (i=0; i<=len; i++) *dst++ = *src++;
 387
 388     len = *src;
 389     if (len == 0 || len >= 0x40 || src[1] != '_') return(mDNSfalse);
 390     for (i=0; i<=len; i++) *dst++ = *src++;
 391
 392     *dst++ = 0;     // Put the null root label on the end of the service type
 393
 394     return(mDNStrue);
 395 }
 396
 397 mDNSlocal void recordstat(HostEntry *entry, const domainname *fqdn, int op, mDNSu16 rrtype)
 398 {
 399     ActivityStat **s = &stats;
 400     domainname srvtype;
 401
 402     if (op != OP_probe)
 403     {
 404         if (rrtype == kDNSType_SRV || rrtype == kDNSType_TXT) op = op - OP_browsegroup + OP_resolvegroup;
 405         else if (rrtype != kDNSType_PTR) return;
 406     }
 407
 408     if (!ExtractServiceType(fqdn, &srvtype)) return;
 409
 410     while (*s && !SameDomainName(&(*s)->srvtype, &srvtype)) s = &(*s)->next;
 411     if (!*s)
 412     {
 413         int i;
 414         *s = malloc(sizeof(ActivityStat));
 415         if (!*s) exit(-1);
 416         (*s)->next     = NULL;
 417         (*s)->srvtype  = srvtype;
 418         (*s)->printed  = 0;
 419         (*s)->totalops = 0;
 420         for (i=0; i<OP_NumTypes; i++) (*s)->stat[i] = 0;
 421     }
 422
 423     (*s)->totalops++;
 424     (*s)->stat[op]++;
 425     if (entry)
 426     {
 427         entry->totalops++;
 428         entry->stat[op]++;
 429     }
 430 }
 431
 432 mDNSlocal void printstats(int max)
 433 {
 434     int i;
 435     if (!stats) return;
 436     for (i=0; i<max; i++)
 437     {
 438         int max = 0;
 439         ActivityStat *s, *m = NULL;
 440         for (s = stats; s; s=s->next)
 441             if (!s->printed && max < s->totalops)
 442             { m = s; max = s->totalops; }
 443         if (!m) return;
 444         m->printed = mDNStrue;
 445         if (i==0) mprintf("%-25s%s\n", "Service Type", OPBanner);
 446         mprintf("%##-25s%8d %8d %8d %8d %8d %8d %8d\n", m->srvtype.c, m->totalops, m->stat[OP_probe],
 447                 m->stat[OP_goodbye], m->stat[OP_browseq], m->stat[OP_browsea], m->stat[OP_resolveq], m->stat[OP_resolvea]);
 448     }
 449 }
 450
 451 mDNSlocal const mDNSu8 *FindUpdate(mDNS *const m, const DNSMessage *const query, const mDNSu8 *ptr, const mDNSu8 *const end,
 452                                    DNSQuestion *q, LargeCacheRecord *pkt)
 453 {
 454     int i;
 455     for (i = 0; i < query->h.numAuthorities; i++)
 456     {
 457         const mDNSu8 *p2 = ptr;
 458         ptr = GetLargeResourceRecord(m, query, ptr, end, q->InterfaceID, kDNSRecordTypePacketAuth, pkt);
 459         if (!ptr) break;
 460         if (m->rec.r.resrec.RecordType != kDNSRecordTypePacketNegative && ResourceRecordAnswersQuestion(&pkt->r.resrec, q)) return(p2);
 461     }
 462     return(mDNSNULL);
 463 }
 464
 465 mDNSlocal void DisplayPacketHeader(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end, const mDNSAddr *srcaddr, mDNSIPPort srcport, const mDNSAddr *dstaddr, const mDNSInterfaceID InterfaceID)
 466 {
 467     const char *const ptype =   (msg->h.flags.b[0] & kDNSFlag0_QR_Response)             ? "-R- " :
 468                               (srcport.NotAnInteger == MulticastDNSPort.NotAnInteger) ? "-Q- " : "-LQ-";
 469
 470     struct timeval tv;
 471     struct tm tm;
 472     const mDNSu32 index = mDNSPlatformInterfaceIndexfromInterfaceID(m, InterfaceID, mDNSfalse);
 473     char if_name[IFNAMSIZ];     // Older Linux distributions don't define IF_NAMESIZE
 474     if_indextoname(index, if_name);
 475     gettimeofday(&tv, NULL);
 476     localtime_r((time_t*)&tv.tv_sec, &tm);
 477     mprintf("\n%d:%02d:%02d.%06d Interface %d/%s\n", tm.tm_hour, tm.tm_min, tm.tm_sec, tv.tv_usec, index, if_name);
 478
 479     mprintf("%#-16a %s             Q:%3d  Ans:%3d  Auth:%3d  Add:%3d  Size:%5d bytes",
 480             srcaddr, ptype, msg->h.numQuestions, msg->h.numAnswers, msg->h.numAuthorities, msg->h.numAdditionals, end - (mDNSu8 *)msg);
 481
 482     if (msg->h.id.NotAnInteger) mprintf("  ID:%u", mDNSVal16(msg->h.id));
 483
 484     if (!mDNSAddrIsDNSMulticast(dstaddr)) mprintf("   To: %#a", dstaddr);
 485
 486     if (msg->h.flags.b[0] & kDNSFlag0_TC)
 487     {
 488         if (msg->h.flags.b[0] & kDNSFlag0_QR_Response) mprintf("   Truncated");
 489         else mprintf("   Truncated (KA list continues in next packet)");
 490     }
 491     mprintf("\n");
 492 }
 493
 494 mDNSlocal void DisplayResourceRecord(const mDNSAddr *const srcaddr, const char *const op, const ResourceRecord *const pktrr)
 495 {
 496     static const char hexchars[16] = "0123456789ABCDEF";
 497     #define MaxWidth 132
 498     char buffer[MaxWidth+8];
 499     char *p = buffer;
 500
 501     RDataBody *rd = &pktrr->rdata->u;
 502     mDNSu8 *rdend = (mDNSu8 *)rd + pktrr->rdlength;
 503     int n = mprintf("%#-16a %-5s %-5s%5lu %##s -> ", srcaddr, op, DNSTypeName(pktrr->rrtype), pktrr->rroriginalttl, pktrr->name->c);
 504
 505     if (pktrr->RecordType == kDNSRecordTypePacketNegative) { mprintf("**** ERROR: FAILED TO READ RDATA ****\n"); return; }
 506
 507     // The kDNSType_OPT case below just calls GetRRDisplayString_rdb
 508     // Perhaps more (or all?) of the cases should do that?
 509     switch(pktrr->rrtype)
 510     {
 511     case kDNSType_A:    n += mprintf("%.4a", &rd->ipv4); break;
 512     case kDNSType_PTR:  n += mprintf("%##.*s", MaxWidth - n, rd->name.c); break;
 513     case kDNSType_HINFO:    // same as kDNSType_TXT below
 514     case kDNSType_TXT:  {
 515         mDNSu8 *t = rd->txt.c;
 516         while (t < rdend && t[0] && p < buffer+MaxWidth)
 517         {
 518             int i;
 519             for (i=1; i<=t[0] && p < buffer+MaxWidth; i++)
 520             {
 521                 if (t[i] == '\\') *p++ = '\\';
 522                 if (t[i] >= ' ') *p++ = t[i];
 523                 else
 524                 {
 525                     *p++ = '\\';
 526                     *p++ = '0';
 527                     *p++ = 'x';
 528                     *p++ = hexchars[t[i] >> 4];
 529                     *p++ = hexchars[t[i] & 0xF];
 530                 }
 531             }
 532             t += 1+t[0];
 533             if (t < rdend && t[0]) { *p++ = '\\'; *p++ = ' '; }
 534         }
 535         *p++ = 0;
 536         n += mprintf("%.*s", MaxWidth - n, buffer);
 537     } break;
 538     case kDNSType_AAAA: n += mprintf("%.16a", &rd->ipv6); break;
 539     case kDNSType_SRV:  n += mprintf("%##s:%d", rd->srv.target.c, mDNSVal16(rd->srv.port)); break;
 540     case kDNSType_OPT:  {
 541         char b[MaxMsg];
 542         // Quick hack: we don't want the prefix that GetRRDisplayString_rdb puts at the start of its
 543         // string, because it duplicates the name and rrtype we already display, so we compute the
 544         // length of that prefix and strip that many bytes off the beginning of the string we display.
 545         mDNSu32 striplen = mDNS_snprintf(b, MaxMsg-1, "%4d %##s %s ", pktrr->rdlength, pktrr->name->c, DNSTypeName(pktrr->rrtype));
 546         GetRRDisplayString_rdb(pktrr, &pktrr->rdata->u, b);
 547         n += mprintf("%.*s", MaxWidth - n, b + striplen);
 548     } break;
 549     case kDNSType_NSEC: {
 550         char b[MaxMsg];
 551         // See the quick hack above
 552         mDNSu32 striplen = mDNS_snprintf(b, MaxMsg-1, "%4d %##s %s ", pktrr->rdlength, pktrr->name->c, DNSTypeName(pktrr->rrtype));
 553         GetRRDisplayString_rdb(pktrr, &pktrr->rdata->u, b);
 554         n += mprintf("%s", b+striplen);
 555     } break;
 556     default:            {
 557         mDNSu8 *s = rd->data;
 558         while (s < rdend && p < buffer+MaxWidth)
 559         {
 560             if (*s == '\\') *p++ = '\\';
 561             if (*s >= ' ') *p++ = *s;
 562             else
 563             {
 564                 *p++ = '\\';
 565                 *p++ = '0';
 566                 *p++ = 'x';
 567                 *p++ = hexchars[*s >> 4];
 568                 *p++ = hexchars[*s & 0xF];
 569             }
 570             s++;
 571         }
 572         *p++ = 0;
 573         n += mprintf("%.*s", MaxWidth - n, buffer);
 574     } break;
 575     }
 576
 577     mprintf("\n");
 578 }
 579
 580 mDNSlocal void HexDump(const mDNSu8 *ptr, const mDNSu8 *const end)
 581 {
 582     while (ptr < end)
 583     {
 584         int i;
 585         for (i=0; i<16; i++)
 586             if (&ptr[i] < end) mprintf("%02X ", ptr[i]);
 587             else mprintf("   ");
 588         for (i=0; i<16; i++)
 589             if (&ptr[i] < end) mprintf("%c", ptr[i] <= ' ' || ptr[i] >= 126 ? '.' : ptr[i]);
 590         ptr += 16;
 591         mprintf("\n");
 592     }
 593 }
 594
 595 mDNSlocal void DisplayError(const mDNSAddr *srcaddr, const mDNSu8 *ptr, const mDNSu8 *const end, char *msg)
 596 {
 597     mprintf("%#-16a **** ERROR: FAILED TO READ %s **** \n", srcaddr, msg);
 598     HexDump(ptr, end);
 599 }
 600
 601 mDNSlocal void DisplayQuery(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end,
 602                             const mDNSAddr *srcaddr, mDNSIPPort srcport, const mDNSAddr *dstaddr, const mDNSInterfaceID InterfaceID)
 603 {
 604     int i;
 605     const mDNSu8 *ptr = msg->data;
 606     const mDNSu8 *auth = LocateAuthorities(msg, end);
 607     mDNSBool MQ = (srcport.NotAnInteger == MulticastDNSPort.NotAnInteger);
 608     HostEntry *entry = GotPacketFromHost(srcaddr, MQ ? HostPkt_Q : HostPkt_L, msg->h.id);
 609     LargeCacheRecord pkt;
 610
 611     DisplayPacketHeader(m, msg, end, srcaddr, srcport, dstaddr, InterfaceID);
 612     if (msg->h.id.NotAnInteger != 0xFFFF)
 613     {
 614         if (MQ) NumPktQ++;else NumPktL++;
 615     }
 616
 617     for (i=0; i<msg->h.numQuestions; i++)
 618     {
 619         DNSQuestion q;
 620         mDNSu8 *p2 = (mDNSu8 *)getQuestion(msg, ptr, end, InterfaceID, &q);
 621         mDNSu16 ucbit = q.qclass & kDNSQClass_UnicastResponse;
 622         q.qclass &= ~kDNSQClass_UnicastResponse;
 623         if (!p2) { DisplayError(srcaddr, ptr, end, "QUESTION"); return; }
 624         ptr = p2;
 625         p2 = (mDNSu8 *)FindUpdate(m, msg, auth, end, &q, &pkt);
 626         if (p2)
 627         {
 628             NumProbes++;
 629             DisplayResourceRecord(srcaddr, ucbit ? "(PU)" : "(PM)", &pkt.r.resrec);
 630             recordstat(entry, &q.qname, OP_probe, q.qtype);
 631             p2 = (mDNSu8 *)skipDomainName(msg, p2, end);
 632             // Having displayed this update record, clear type and class so we don't display the same one again.
 633             p2[0] = p2[1] = p2[2] = p2[3] = 0;
 634         }
 635         else
 636         {
 637             const char *ptype = ucbit ? "(QU)" : "(QM)";
 638             if (srcport.NotAnInteger == MulticastDNSPort.NotAnInteger) NumQuestions++;
 639             else { NumLegacy++; ptype = "(LQ)"; }
 640             mprintf("%#-16a %-5s %-5s      %##s\n", srcaddr, ptype, DNSTypeName(q.qtype), q.qname.c);
 641             if (msg->h.id.NotAnInteger != 0xFFFF) recordstat(entry, &q.qname, OP_query, q.qtype);
 642         }
 643     }
 644
 645     for (i=0; i<msg->h.numAnswers; i++)
 646     {
 647         const mDNSu8 *ep = ptr;
 648         ptr = GetLargeResourceRecord(m, msg, ptr, end, InterfaceID, kDNSRecordTypePacketAns, &pkt);
 649         if (!ptr) { DisplayError(srcaddr, ep, end, "KNOWN ANSWER"); return; }
 650         DisplayResourceRecord(srcaddr, "(KA)", &pkt.r.resrec);
 651
 652         // In the case of queries with long multi-packet KA lists, we count each subsequent KA packet
 653         // the same as a single query, to more accurately reflect the burden on the network
 654         // (A query with a six-packet KA list is *at least* six times the burden on the network as a single-packet query.)
 655         if (msg->h.numQuestions == 0 && i == 0)
 656             recordstat(entry, pkt.r.resrec.name, OP_query, pkt.r.resrec.rrtype);
 657     }
 658
 659     for (i=0; i<msg->h.numAuthorities; i++)
 660     {
 661         const mDNSu8 *ep = ptr;
 662         ptr = GetLargeResourceRecord(m, msg, ptr, end, InterfaceID, kDNSRecordTypePacketAuth, &pkt);
 663         if (!ptr) { DisplayError(srcaddr, ep, end, "AUTHORITY"); return; }
 664         // After we display an Update record with its matching question (above) we zero out its type and class
 665         // If any remain that haven't been zero'd out, display them here
 666         if (pkt.r.resrec.rrtype || pkt.r.resrec.rrclass) DisplayResourceRecord(srcaddr, "(AU)", &pkt.r.resrec);
 667     }
 668
 669     for (i=0; i<msg->h.numAdditionals; i++)
 670     {
 671         const mDNSu8 *ep = ptr;
 672         ptr = GetLargeResourceRecord(m, msg, ptr, end, InterfaceID, kDNSRecordTypePacketAdd, &pkt);
 673         if (!ptr) { DisplayError(srcaddr, ep, end, "ADDITIONAL"); return; }
 674         DisplayResourceRecord(srcaddr, pkt.r.resrec.rrtype == kDNSType_OPT ? "(OP)" : "(AD)", &pkt.r.resrec);
 675     }
 676
 677     if (entry) AnalyseHost(m, entry, InterfaceID);
 678 }
 679
 680 mDNSlocal void DisplayResponse(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *end,
 681                                const mDNSAddr *srcaddr, mDNSIPPort srcport, const mDNSAddr *dstaddr, const mDNSInterfaceID InterfaceID)
 682 {
 683     int i;
 684     const mDNSu8 *ptr = msg->data;
 685     HostEntry *entry = GotPacketFromHost(srcaddr, HostPkt_R, msg->h.id);
 686     LargeCacheRecord pkt;
 687
 688     DisplayPacketHeader(m, msg, end, srcaddr, srcport, dstaddr, InterfaceID);
 689     if (msg->h.id.NotAnInteger != 0xFFFF) NumPktR++;
 690
 691     for (i=0; i<msg->h.numQuestions; i++)
 692     {
 693         DNSQuestion q;
 694         const mDNSu8 *ep = ptr;
 695         ptr = getQuestion(msg, ptr, end, InterfaceID, &q);
 696         if (!ptr) { DisplayError(srcaddr, ep, end, "QUESTION"); return; }
 697         if (mDNSAddrIsDNSMulticast(dstaddr))
 698             mprintf("%#-16a (?)   **** ERROR: SHOULD NOT HAVE Q IN mDNS RESPONSE **** %-5s %##s\n", srcaddr, DNSTypeName(q.qtype), q.qname.c);
 699         else
 700             mprintf("%#-16a (Q)   %-5s      %##s\n", srcaddr, DNSTypeName(q.qtype), q.qname.c);
 701     }
 702
 703     for (i=0; i<msg->h.numAnswers; i++)
 704     {
 705         const mDNSu8 *ep = ptr;
 706         ptr = GetLargeResourceRecord(m, msg, ptr, end, InterfaceID, kDNSRecordTypePacketAns, &pkt);
 707         if (!ptr) { DisplayError(srcaddr, ep, end, "ANSWER"); return; }
 708         if (pkt.r.resrec.rroriginalttl)
 709         {
 710             NumAnswers++;
 711             DisplayResourceRecord(srcaddr, (pkt.r.resrec.RecordType & kDNSRecordTypePacketUniqueMask) ? "(AN)" : "(AN+)", &pkt.r.resrec);
 712             if (msg->h.id.NotAnInteger != 0xFFFF) recordstat(entry, pkt.r.resrec.name, OP_answer, pkt.r.resrec.rrtype);
 713             if (entry) RecordHostInfo(entry, &pkt.r.resrec);
 714         }
 715         else
 716         {
 717             NumGoodbyes++;
 718             DisplayResourceRecord(srcaddr, "(DE)", &pkt.r.resrec);
 719             recordstat(entry, pkt.r.resrec.name, OP_goodbye, pkt.r.resrec.rrtype);
 720         }
 721     }
 722
 723     for (i=0; i<msg->h.numAuthorities; i++)
 724     {
 725         const mDNSu8 *ep = ptr;
 726         ptr = GetLargeResourceRecord(m, msg, ptr, end, InterfaceID, kDNSRecordTypePacketAuth, &pkt);
 727         if (!ptr) { DisplayError(srcaddr, ep, end, "AUTHORITY"); return; }
 728         mprintf("%#-16a (?)  **** ERROR: SHOULD NOT HAVE AUTHORITY IN mDNS RESPONSE **** %-5s %##s\n",
 729                 srcaddr, DNSTypeName(pkt.r.resrec.rrtype), pkt.r.resrec.name->c);
 730     }
 731
 732     for (i=0; i<msg->h.numAdditionals; i++)
 733     {
 734         const mDNSu8 *ep = ptr;
 735         ptr = GetLargeResourceRecord(m, msg, ptr, end, InterfaceID, kDNSRecordTypePacketAdd, &pkt);
 736         if (!ptr) { DisplayError(srcaddr, ep, end, "ADDITIONAL"); return; }
 737         NumAdditionals++;
 738         DisplayResourceRecord(srcaddr,
 739                               pkt.r.resrec.rrtype == kDNSType_OPT ? "(OP)" : (pkt.r.resrec.RecordType & kDNSRecordTypePacketUniqueMask) ? "(AD)" : "(AD+)",
 740                               &pkt.r.resrec);
 741         if (entry) RecordHostInfo(entry, &pkt.r.resrec);
 742     }
 743
 744     if (entry) AnalyseHost(m, entry, InterfaceID);
 745 }
 746
 747 mDNSlocal void ProcessUnicastResponse(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *end, const mDNSAddr *srcaddr, const mDNSInterfaceID InterfaceID)
 748 {
 749     int i;
 750     const mDNSu8 *ptr = LocateAnswers(msg, end);
 751     HostEntry *entry = GotPacketFromHost(srcaddr, HostPkt_R, msg->h.id);
 752     //mprintf("%#a R\n", srcaddr);
 753
 754     for (i=0; i<msg->h.numAnswers + msg->h.numAuthorities + msg->h.numAdditionals; i++)
 755     {
 756         LargeCacheRecord pkt;
 757         ptr = GetLargeResourceRecord(m, msg, ptr, end, InterfaceID, kDNSRecordTypePacketAns, &pkt);
 758         if (ptr && pkt.r.resrec.rroriginalttl && entry) RecordHostInfo(entry, &pkt.r.resrec);
 759     }
 760 }
 761
 762 mDNSlocal mDNSBool AddressMatchesFilterList(const mDNSAddr *srcaddr)
 763 {
 764     FilterList *f;
 765     if (!Filters) return(srcaddr->type == mDNSAddrType_IPv4);
 766     for (f=Filters; f; f=f->next) if (mDNSSameAddress(srcaddr, &f->FilterAddr)) return(mDNStrue);
 767     return(mDNSfalse);
 768 }
 769
 770 mDNSexport void mDNSCoreReceive(mDNS *const m, DNSMessage *const msg, const mDNSu8 *const end,
 771                                 const mDNSAddr *srcaddr, mDNSIPPort srcport, const mDNSAddr *dstaddr, mDNSIPPort dstport, const mDNSInterfaceID InterfaceID)
 772 {
 773     const mDNSu8 StdQ = kDNSFlag0_QR_Query    | kDNSFlag0_OP_StdQuery;
 774     const mDNSu8 StdR = kDNSFlag0_QR_Response | kDNSFlag0_OP_StdQuery;
 775     const mDNSu8 QR_OP = (mDNSu8)(msg->h.flags.b[0] & kDNSFlag0_QROP_Mask);
 776     mDNSu8 *ptr = (mDNSu8 *)&msg->h.numQuestions;
 777     int goodinterface = (FilterInterface == 0);
 778
 779     (void)dstaddr;  // Unused
 780     (void)dstport;  // Unused
 781
 782     // Read the integer parts which are in IETF byte-order (MSB first, LSB second)
 783     msg->h.numQuestions   = (mDNSu16)((mDNSu16)ptr[0] <<  8 | ptr[1]);
 784     msg->h.numAnswers     = (mDNSu16)((mDNSu16)ptr[2] <<  8 | ptr[3]);
 785     msg->h.numAuthorities = (mDNSu16)((mDNSu16)ptr[4] <<  8 | ptr[5]);
 786     msg->h.numAdditionals = (mDNSu16)((mDNSu16)ptr[6] <<  8 | ptr[7]);
 787
 788     // For now we're only interested in monitoring IPv4 traffic.
 789     // All IPv6 packets should just be duplicates of the v4 packets.
 790     if (!goodinterface) goodinterface = (FilterInterface == (int)mDNSPlatformInterfaceIndexfromInterfaceID(m, InterfaceID, mDNSfalse));
 791     if (goodinterface && AddressMatchesFilterList(srcaddr))
 792     {
 793         mDNS_Lock(m);
 794         if (!mDNSAddrIsDNSMulticast(dstaddr))
 795         {
 796             if      (QR_OP == StdQ) mprintf("Unicast query from %#a\n", srcaddr);
 797             else if (QR_OP == StdR) ProcessUnicastResponse(m, msg, end, srcaddr,                   InterfaceID);
 798         }
 799         else
 800         {
 801             if      (QR_OP == StdQ) DisplayQuery          (m, msg, end, srcaddr, srcport, dstaddr, InterfaceID);
 802             else if (QR_OP == StdR) DisplayResponse       (m, msg, end, srcaddr, srcport, dstaddr, InterfaceID);
 803             else
 804             {
 805                 debugf("Unknown DNS packet type %02X%02X (ignored)", msg->h.flags.b[0], msg->h.flags.b[1]);
 806                 GotPacketFromHost(srcaddr, HostPkt_B, msg->h.id);
 807                 NumPktB++;
 808             }
 809         }
 810         mDNS_Unlock(m);
 811     }
 812 }
 813
 814 mDNSlocal mStatus mDNSNetMonitor(void)
 815 {
 816     struct tm tm;
 817     int h, m, s, mul, div, TotPkt;
 818 #if !defined(WIN32)
 819     sigset_t signals;
 820 #endif
 821
 822     mStatus status = mDNS_Init(&mDNSStorage, &PlatformStorage,
 823                                mDNS_Init_NoCache, mDNS_Init_ZeroCacheSize,
 824                                mDNS_Init_DontAdvertiseLocalAddresses,
 825                                mDNS_Init_NoInitCallback, mDNS_Init_NoInitCallbackContext);
 826     if (status) return(status);
 827
 828     gettimeofday(&tv_start, NULL);
 829
 830 #if defined( WIN32 )
 831     status = SetupInterfaceList(&mDNSStorage);
 832     if (status) return(status);
 833     gStopEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
 834     if (gStopEvent == INVALID_HANDLE_VALUE) return mStatus_UnknownErr;
 835     mDNSPollRegisterEvent( gStopEvent, StopNotification, NULL );
 836     if (!SetConsoleCtrlHandler(ConsoleControlHandler, TRUE)) return mStatus_UnknownErr;
 837     gRunning = mDNStrue; while (gRunning) mDNSPoll( INFINITE );
 838     if (!SetConsoleCtrlHandler(ConsoleControlHandler, FALSE)) return mStatus_UnknownErr;
 839     CloseHandle(gStopEvent);
 840 #else
 841     mDNSPosixListenForSignalInEventLoop(SIGINT);
 842     mDNSPosixListenForSignalInEventLoop(SIGTERM);
 843
 844     do
 845     {
 846         struct timeval timeout = { 0x3FFFFFFF, 0 };     // wait until SIGINT or SIGTERM
 847         mDNSBool gotSomething;
 848         mDNSPosixRunEventLoopOnce(&mDNSStorage, &timeout, &signals, &gotSomething);
 849     }
 850     while ( !( sigismember( &signals, SIGINT) || sigismember( &signals, SIGTERM)));
 851 #endif
 852
 853     // Now display final summary
 854     TotPkt = NumPktQ + NumPktL + NumPktR;
 855     gettimeofday(&tv_end, NULL);
 856     tv_interval = tv_end;
 857     if (tv_start.tv_usec > tv_interval.tv_usec)
 858     { tv_interval.tv_usec += 1000000; tv_interval.tv_sec--; }
 859     tv_interval.tv_sec  -= tv_start.tv_sec;
 860     tv_interval.tv_usec -= tv_start.tv_usec;
 861     h = (tv_interval.tv_sec / 3600);
 862     m = (tv_interval.tv_sec % 3600) / 60;
 863     s = (tv_interval.tv_sec % 60);
 864     if (tv_interval.tv_sec > 10)
 865     {
 866         mul = 60;
 867         div = tv_interval.tv_sec;
 868     }
 869     else
 870     {
 871         mul = 60000;
 872         div = tv_interval.tv_sec * 1000 + tv_interval.tv_usec / 1000;
 873         if (div == 0) div=1;
 874     }
 875
 876     mprintf("\n\n");
 877     localtime_r((time_t*)&tv_start.tv_sec, &tm);
 878     mprintf("Started      %3d:%02d:%02d.%06d\n", tm.tm_hour, tm.tm_min, tm.tm_sec, tv_start.tv_usec);
 879     localtime_r((time_t*)&tv_end.tv_sec, &tm);
 880     mprintf("End          %3d:%02d:%02d.%06d\n", tm.tm_hour, tm.tm_min, tm.tm_sec, tv_end.tv_usec);
 881     mprintf("Captured for %3d:%02d:%02d.%06d\n", h, m, s, tv_interval.tv_usec);
 882     if (!Filters)
 883     {
 884         mprintf("Unique source addresses seen on network:");
 885         if (IPv4HostList.num) mprintf(" %ld (IPv4)", IPv4HostList.num);
 886         if (IPv6HostList.num) mprintf(" %ld (IPv6)", IPv6HostList.num);
 887         if (!IPv4HostList.num && !IPv6HostList.num) mprintf(" None");
 888         mprintf("\n");
 889     }
 890     mprintf("\n");
 891     mprintf("Modern Query        Packets:      %7d   (avg%5d/min)\n", NumPktQ,        NumPktQ        * mul / div);
 892     mprintf("Legacy Query        Packets:      %7d   (avg%5d/min)\n", NumPktL,        NumPktL        * mul / div);
 893     mprintf("Multicast Response  Packets:      %7d   (avg%5d/min)\n", NumPktR,        NumPktR        * mul / div);
 894     mprintf("Total     Multicast Packets:      %7d   (avg%5d/min)\n", TotPkt,         TotPkt         * mul / div);
 895     mprintf("\n");
 896     mprintf("Total New Service Probes:         %7d   (avg%5d/min)\n", NumProbes,      NumProbes      * mul / div);
 897     mprintf("Total Goodbye Announcements:      %7d   (avg%5d/min)\n", NumGoodbyes,    NumGoodbyes    * mul / div);
 898     mprintf("Total Query Questions:            %7d   (avg%5d/min)\n", NumQuestions,   NumQuestions   * mul / div);
 899     mprintf("Total Queries from Legacy Clients:%7d   (avg%5d/min)\n", NumLegacy,      NumLegacy      * mul / div);
 900     mprintf("Total Answers/Announcements:      %7d   (avg%5d/min)\n", NumAnswers,     NumAnswers     * mul / div);
 901     mprintf("Total Additional Records:         %7d   (avg%5d/min)\n", NumAdditionals, NumAdditionals * mul / div);
 902     mprintf("\n");
 903     printstats(kReportTopServices);
 904
 905     if (!ExactlyOneFilter)
 906     {
 907         ShowSortedHostList(&IPv4HostList, kReportTopHosts);
 908         ShowSortedHostList(&IPv6HostList, kReportTopHosts);
 909     }
 910
 911     mDNS_Close(&mDNSStorage);
 912     return(0);
 913 }
 914
 915 mDNSexport int main(int argc, char **argv)
 916 {
 917     const char *progname = strrchr(argv[0], '/') ? strrchr(argv[0], '/') + 1 : argv[0];
 918     int i;
 919     mStatus status;
 920
 921 #if defined(WIN32)
 922     HeapSetInformation(NULL, HeapEnableTerminationOnCorruption, NULL, 0);
 923 #endif
 924
 925     setlinebuf(stdout);             // Want to see lines as they appear, not block buffered
 926
 927     for (i=1; i<argc; i++)
 928     {
 929         if (i+1 < argc && !strcmp(argv[i], "-i") && atoi(argv[i+1]))
 930         {
 931             FilterInterface = atoi(argv[i+1]);
 932             i += 2;
 933             printf("Monitoring interface %d\n", FilterInterface);
 934         }
 935         else
 936         {
 937             struct in_addr s4;
 938             struct in6_addr s6;
 939             FilterList *f;
 940             mDNSAddr a;
 941             a.type = mDNSAddrType_IPv4;
 942
 943             if (inet_pton(AF_INET, argv[i], &s4) == 1)
 944                 a.ip.v4.NotAnInteger = s4.s_addr;
 945             else if (inet_pton(AF_INET6, argv[i], &s6) == 1)
 946             {
 947                 a.type = mDNSAddrType_IPv6;
 948                 mDNSPlatformMemCopy(&a.ip.v6, &s6, sizeof(a.ip.v6));
 949             }
 950             else
 951             {
 952                 struct hostent *h = gethostbyname(argv[i]);
 953                 if (h) a.ip.v4.NotAnInteger = *(long*)h->h_addr;
 954                 else goto usage;
 955             }
 956
 957             f = malloc(sizeof(*f));
 958             f->FilterAddr = a;
 959             f->next = Filters;
 960             Filters = f;
 961         }
 962     }
 963
 964     status = mDNSNetMonitor();
 965     if (status) { fprintf(stderr, "%s: mDNSNetMonitor failed %d\n", progname, (int)status); return(status); }
 966     return(0);
 967
 968 usage:
 969     fprintf(stderr, "\nmDNS traffic monitor\n");
 970     fprintf(stderr, "Usage: %s [-i index] [host]\n", progname);
 971     fprintf(stderr, "Optional [-i index] parameter displays only packets from that interface index\n");
 972     fprintf(stderr, "Optional [host] parameter displays only packets from that host\n");
 973
 974     fprintf(stderr, "\nPer-packet header output:\n");
 975     fprintf(stderr, "-Q-            Multicast Query from mDNS client that accepts multicast responses\n");
 976     fprintf(stderr, "-R-            Multicast Response packet containing answers/announcements\n");
 977     fprintf(stderr, "-LQ-           Multicast Query from legacy client that does *not* listen for multicast responses\n");
 978     fprintf(stderr, "Q/Ans/Auth/Add Number of questions, answers, authority records and additional records in packet\n");
 979
 980     fprintf(stderr, "\nPer-record display:\n");
 981     fprintf(stderr, "(PM)           Probe Question (new service starting), requesting multicast response\n");
 982     fprintf(stderr, "(PU)           Probe Question (new service starting), requesting unicast response\n");
 983     fprintf(stderr, "(DE)           Deletion/Goodbye (service going away)\n");
 984     fprintf(stderr, "(LQ)           Legacy Query Question\n");
 985     fprintf(stderr, "(QM)           Query Question, requesting multicast response\n");
 986     fprintf(stderr, "(QU)           Query Question, requesting unicast response\n");
 987     fprintf(stderr, "(KA)           Known Answer (information querier already knows)\n");
 988     fprintf(stderr, "(AN)           Unique Answer to question (or periodic announcment) (entire RR Set)\n");
 989     fprintf(stderr, "(AN+)          Answer to question (or periodic announcment) (add to existing RR Set members)\n");
 990     fprintf(stderr, "(AD)           Unique Additional Record Set (entire RR Set)\n");
 991     fprintf(stderr, "(AD+)          Additional records (add to existing RR Set members)\n");
 992
 993     fprintf(stderr, "\nFinal summary, sorted by service type:\n");
 994     fprintf(stderr, "Probe          Probes for this service type starting up\n");
 995     fprintf(stderr, "Goodbye        Goodbye (deletion) packets for this service type shutting down\n");
 996     fprintf(stderr, "BrowseQ        Browse questions from clients browsing to find a list of instances of this service\n");
 997     fprintf(stderr, "BrowseA        Browse answers/announcments advertising instances of this service\n");
 998     fprintf(stderr, "ResolveQ       Resolve questions from clients actively connecting to an instance of this service\n");
 999     fprintf(stderr, "ResolveA       Resolve answers/announcments giving connection information for an instance of this service\n");
1000     fprintf(stderr, "\n");
1001     return(-1);
1002 }