text: /* -*- Mode: C; tab-width: 4 -*-
   *
   * Copyright (c) 2002-2004 Apple Computer, Inc. All rights reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   * 
   *     http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   * Formatting notes:
   * This code follows the "Whitesmiths style" C indentation rules. Plenty of discussion
   * on C indentation can be found on the web, such as <http://www.kafejo.com/komp/1tbs.htm>,
   * but for the sake of brevity here I will say just this: Curly braces are not syntactially
   * part of an "if" statement; they are the beginning and ending markers of a compound statement;
   * therefore common sense dictates that if they are part of a compound statement then they
   * should be indented to the same level as everything else in that compound statement.
   * Indenting curly braces at the same level as the "if" implies that curly braces are
   * part of the "if", which is false. (This is as misleading as people who write "char* x,y;"
   * thinking that variables x and y are both of type "char*" -- and anyone who doesn't
   * understand why variable y is not of type "char*" just proves the point that poor code
   * layout leads people to unfortunate misunderstandings about how the C language really works.)
   */
  
  //*************************************************************************************************************
  // Incorporate mDNS.c functionality
  
  // We want to use the functionality provided by "mDNS.c",
  // except we'll sneak a peek at the packets before forwarding them to the normal mDNSCoreReceive() routine
  #define mDNSCoreReceive __MDNS__mDNSCoreReceive
  #include "mDNS.c"
  #undef mDNSCoreReceive
  
  //*************************************************************************************************************
  // Headers
  
  #include <unistd.h>
  #include <stdio.h>
  #include <string.h>
  #include <errno.h>
  #include <sys/socket.h>
  #include <netinet/in.h>
  #include <netinet/in_systm.h>		// For n_long, required by <netinet/ip.h> below
  #include <netinet/ip.h>				// For IPTOS_LOWDELAY etc.
  #include <arpa/inet.h>
  #include <signal.h>
  
  #include "mDNSEmbeddedAPI.h"// Defines the interface to the mDNS core code
  #include "mDNSPosix.h"    // Defines the specific types needed to run mDNS on this platform
  #include "ExampleClientApp.h"
  
  //*************************************************************************************************************
  // Globals
  
  static mDNS mDNSStorage;       // mDNS core uses this to store its globals
  static mDNS_PlatformSupport PlatformStorage;  // Stores this platform's globals
  #define RR_CACHE_SIZE 500
  static CacheEntity gRRCache[RR_CACHE_SIZE];
  mDNSexport const char ProgramName[] = "mDNSIdentify";
  
  static volatile int StopNow;	// 0 means running, 1 means stop because we got an answer, 2 means stop because of Ctrl-C
  static volatile int NumAnswers, NumAddr, NumAAAA, NumHINFO;
  static char hostname[MAX_ESCAPED_DOMAIN_NAME], hardware[256], software[256];
  static mDNSAddr lastsrc, hostaddr, target;
  static mDNSOpaque16 lastid, id;
  
  //*************************************************************************************************************
  // Utilities
  
  // Special version of printf that knows how to print IP addresses, DNS-format name strings, etc.
  mDNSlocal mDNSu32 mprintf(const char *format, ...) IS_A_PRINTF_STYLE_FUNCTION(1,2);
  mDNSlocal mDNSu32 mprintf(const char *format, ...)
  	{
  	mDNSu32 length;
  	unsigned char buffer[512];
  	va_list ptr;
  	va_start(ptr,format);
  	length = mDNS_vsnprintf((char *)buffer, sizeof(buffer), format, ptr);
  	va_end(ptr);
  	printf("%s", buffer);
  	return(length);
  	}
  
  //*************************************************************************************************************
  // Main code
  
  mDNSexport void mDNSCoreReceive(mDNS *const m, DNSMessage *const msg, const mDNSu8 *const end,
  	const mDNSAddr *const srcaddr, const mDNSIPPort srcport, const mDNSAddr *const dstaddr, const mDNSIPPort dstport,
  	const mDNSInterfaceID InterfaceID)
  	{
  	(void)dstaddr; // Unused
  	// Snag copy of header ID, then call through
  	lastid = msg->h.id;
  	lastsrc = *srcaddr;
  
  	// We *want* to allow off-net unicast responses here.
  	// For now, the simplest way to allow that is to pretend it was received via multicast so that mDNSCore doesn't reject the packet
  	__MDNS__mDNSCoreReceive(m, msg, end, srcaddr, srcport, &AllDNSLinkGroup_v4, dstport, InterfaceID);
  	}
  
  mDNSlocal void NameCallback(mDNS *const m, DNSQuestion *question, const ResourceRecord *const answer, QC_result AddRecord)
  	{
  	(void)m;		// Unused
  	(void)question;	// Unused
  	(void)AddRecord;// Unused
  	if (!id.NotAnInteger) id = lastid;
  	if (answer->rrtype == kDNSType_PTR || answer->rrtype == kDNSType_CNAME)
  		{
  		ConvertDomainNameToCString(&answer->rdata->u.name, hostname);
  		StopNow = 1;
  		mprintf("%##s %s %##s\n", answer->name->c, DNSTypeName(answer->rrtype), answer->rdata->u.name.c);
  		}
  	}
  
  mDNSlocal void InfoCallback(mDNS *const m, DNSQuestion *question, const ResourceRecord *const answer, QC_result AddRecord)
  	{
  	(void)m;		// Unused
  	(void)question;	// Unused
  	(void)AddRecord;// Unused
  	if (answer->rrtype == kDNSType_A)
  		{
  		if (!id.NotAnInteger) id = lastid;
  		NumAnswers++;
  		NumAddr++;
  		mprintf("%##s %s %.4a\n", answer->name->c, DNSTypeName(answer->rrtype), &answer->rdata->u.ipv4);
  		hostaddr.type = mDNSAddrType_IPv4;	// Prefer v4 target to v6 target, for now
  		hostaddr.ip.v4 = answer->rdata->u.ipv4;
  		}
  	else if (answer->rrtype == kDNSType_AAAA)
  		{
  		if (!id.NotAnInteger) id = lastid;
  		NumAnswers++;
  		NumAAAA++;
  		mprintf("%##s %s %.16a\n", answer->name->c, DNSTypeName(answer->rrtype), &answer->rdata->u.ipv6);
  		if (!hostaddr.type)	// Prefer v4 target to v6 target, for now
  			{
  			hostaddr.type = mDNSAddrType_IPv6;
  			hostaddr.ip.v6 = answer->rdata->u.ipv6;
  			}
  		}
  	else if (answer->rrtype == kDNSType_HINFO)
  		{
  		mDNSu8 *p = answer->rdata->u.data;
  		strncpy(hardware, (char*)(p+1), p[0]);
  		hardware[p[0]] = 0;
  		p += 1 + p[0];
  		strncpy(software, (char*)(p+1), p[0]);
  		software[p[0]] = 0;
  		NumAnswers++;
  		NumHINFO++;
  		}
  
  	// If we've got everything we're looking for, don't need to wait any more
  	if (/*NumHINFO && */ (NumAddr || NumAAAA)) StopNow = 1;
  	}
  
  mDNSlocal void ServicesCallback(mDNS *const m, DNSQuestion *question, const ResourceRecord *const answer, QC_result AddRecord)
  	{
  	(void)m;		// Unused
  	(void)question;	// Unused
  	(void)AddRecord;// Unused
  	// Right now the mDNSCore targeted-query code is incomplete --
  	// it issues targeted queries, but accepts answers from anywhere
  	// For now, we'll just filter responses here so we don't get confused by responses from someone else
  	if (answer->rrtype == kDNSType_PTR && mDNSSameAddress(&lastsrc, &target))
  		{
  		NumAnswers++;
  		mprintf("%##s %s %##s\n", answer->name->c, DNSTypeName(answer->rrtype), answer->rdata->u.name.c);
  		}
  	}
  
  mDNSlocal void WaitForAnswer(mDNS *const m, int seconds)
  	{
  	struct timeval end;
  	gettimeofday(&end, NULL);
  	end.tv_sec += seconds;
  	StopNow = 0;
  	NumAnswers = 0;
  	while (!StopNow)
  		{
  		int nfds = 0;
  		fd_set readfds;
  		struct timeval now, remain = end;
  		int result;
  
  		FD_ZERO(&readfds);
  		gettimeofday(&now, NULL);
  		if (remain.tv_usec < now.tv_usec) { remain.tv_usec += 1000000; remain.tv_sec--; }
  		if (remain.tv_sec < now.tv_sec)
  			{
  			if (!NumAnswers) printf("No response after %d seconds\n", seconds);
  			return;
  			}
  		remain.tv_usec -= now.tv_usec;
  		remain.tv_sec  -= now.tv_sec;
  		mDNSPosixGetFDSet(m, &nfds, &readfds, &remain);
  		result = select(nfds, &readfds, NULL, NULL, &remain);
  		if (result >= 0) mDNSPosixProcessFDSet(m, &readfds);
  		else if (errno != EINTR) StopNow = 2;
  		}
  	}
  
  mDNSlocal mStatus StartQuery(DNSQuestion *q, char *qname, mDNSu16 qtype, const mDNSAddr *target, mDNSQuestionCallback callback)
  	{
  	lastsrc = zeroAddr;
  	if (qname) MakeDomainNameFromDNSNameString(&q->qname, qname);
  	q->InterfaceID      = mDNSInterface_Any;
  	q->Target           = target ? *target : zeroAddr;
  	q->TargetPort       = MulticastDNSPort;
  	q->TargetQID        = zeroID;
  	q->qtype            = qtype;
  	q->qclass           = kDNSClass_IN;
  	q->LongLived        = mDNSfalse;
  	q->ExpectUnique     = mDNSfalse;	// Don't want to stop after the first response packet
  	q->ForceMCast       = mDNStrue;		// Query via multicast, even for apparently uDNS names like 1.1.1.17.in-addr.arpa.
  	q->ReturnIntermed   = mDNStrue;
  	q->SuppressUnusable = mDNSfalse;
  	q->SearchListIndex  = 0;
  	q->AppendSearchDomains = 0;
  	q->RetryWithSearchDomains = mDNSfalse;
  	q->TimeoutQuestion  = 0;
  	q->WakeOnResolve    = 0;
  	q->qnameOrig        = mDNSNULL;
  	q->QuestionCallback = callback;
  	q->QuestionContext  = NULL;
  
  	//mprintf("%##s %s ?\n", q->qname.c, DNSTypeName(qtype));
  	return(mDNS_StartQuery(&mDNSStorage, q));
  	}
  
  mDNSlocal void DoOneQuery(DNSQuestion *q, char *qname, mDNSu16 qtype, const mDNSAddr *target, mDNSQuestionCallback callback)
  	{
  	mStatus status = StartQuery(q, qname, qtype, target, callback);
  	if (status != mStatus_NoError)
  		StopNow = 2;
  	else
  		{
  		WaitForAnswer(&mDNSStorage, 4);
  		mDNS_StopQuery(&mDNSStorage, q);
  		}
  	}
  
  mDNSlocal int DoQuery(DNSQuestion *q, char *qname, mDNSu16 qtype, const mDNSAddr *target, mDNSQuestionCallback callback)
  	{
  	DoOneQuery(q, qname, qtype, target, callback);
  	if (StopNow == 0 && NumAnswers == 0 && target && target->type)
  		{
  		mprintf("%##s %s Trying multicast\n", q->qname.c, DNSTypeName(q->qtype));
  		DoOneQuery(q, qname, qtype, NULL, callback);
  		}
  	if (StopNow == 0 && NumAnswers == 0)
  		mprintf("%##s %s *** No Answer ***\n", q->qname.c, DNSTypeName(q->qtype));
  	return(StopNow);
  	}
  
  mDNSlocal void HandleSIG(int signal)
  	{
  	(void)signal;	// Unused
  	debugf("%s","");
  	debugf("HandleSIG");
  	StopNow = 2;
  	}
  
  mDNSexport int main(int argc, char **argv)
  	{
  	const char *progname = strrchr(argv[0], '/') ? strrchr(argv[0], '/') + 1 : argv[0];
  	int this_arg = 1;
  	mStatus status;
  	struct in_addr s4;
  #if HAVE_IPV6
  	struct in6_addr s6;
  #endif
  	char buffer[256];
  	DNSQuestion q;
  
  	if (argc < 2) goto usage;
  	
  	// Since this is a special command-line tool, we want LogMsg() errors to go to stderr, not syslog
  	mDNS_DebugMode = mDNStrue;
  	
      // Initialise the mDNS core.
  	status = mDNS_Init(&mDNSStorage, &PlatformStorage,
      	gRRCache, RR_CACHE_SIZE,
      	mDNS_Init_DontAdvertiseLocalAddresses,
      	mDNS_Init_NoInitCallback, mDNS_Init_NoInitCallbackContext);
  	if (status) { fprintf(stderr, "Daemon start: mDNS_Init failed %d\n", (int)status); return(status); }
  
  	signal(SIGINT, HandleSIG);	// SIGINT is what you get for a Ctrl-C
  	signal(SIGTERM, HandleSIG);
  
  	while (this_arg < argc)
  		{
  		char *arg = argv[this_arg++];
  		if (this_arg > 2) printf("\n");
  
  		lastid = id = zeroID;
  		hostaddr = target = zeroAddr;
  		hostname[0] = hardware[0] = software[0] = 0;
  		NumAddr = NumAAAA = NumHINFO = 0;
  
  		if (inet_pton(AF_INET, arg, &s4) == 1)
  			{
  			mDNSu8 *p = (mDNSu8 *)&s4;
  			// Note: This is reverse order compared to a normal dotted-decimal IP address, so we can't use our customary "%.4a" format code
  			mDNS_snprintf(buffer, sizeof(buffer), "%d.%d.%d.%d.in-addr.arpa.", p[3], p[2], p[1], p[0]);
  			printf("%s\n", buffer);
  			target.type = mDNSAddrType_IPv4;
  			target.ip.v4.NotAnInteger = s4.s_addr;
  			DoQuery(&q, buffer, kDNSType_PTR, &target, NameCallback);
  			if (StopNow == 2) break;
  			}
  #if HAVE_IPV6
  		else if (inet_pton(AF_INET6, arg, &s6) == 1)
  			{
  			int i;
  			mDNSu8 *p = (mDNSu8 *)&s6;
  			for (i = 0; i < 16; i++)
  				{
  				static const char hexValues[] = "0123456789ABCDEF";
  				buffer[i * 4    ] = hexValues[p[15-i] & 0x0F];
  				buffer[i * 4 + 1] = '.';
  				buffer[i * 4 + 2] = hexValues[p[15-i] >> 4];
  				buffer[i * 4 + 3] = '.';
  				}
  			mDNS_snprintf(&buffer[64], sizeof(buffer)-64, "ip6.arpa.");
  			target.type = mDNSAddrType_IPv6;
  			mDNSPlatformMemCopy(&target.ip.v6, &s6, sizeof(target.ip.v6));
  			DoQuery(&q, buffer, kDNSType_PTR, &target, NameCallback);
  			if (StopNow == 2) break;
  			}
  #endif
  		else {
  			if (strlen(arg) >= sizeof(hostname)) {
  				fprintf(stderr, "hostname must be < %d characters\n", (int)sizeof(hostname));
  				goto usage;
  			}
  			strcpy(hostname, arg);
  		}
  	
  		// Now we have the host name; get its A, AAAA, and HINFO
  		if (hostname[0]) DoQuery(&q, hostname, kDNSQType_ANY, &target, InfoCallback);
  		if (StopNow == 2) break;
  	
  		if (hardware[0] || software[0])
  			{
  			printf("HINFO Hardware: %s\n", hardware);
  			printf("HINFO Software: %s\n", software);
  			}
  		else if (NumAnswers) printf("%s has no HINFO record\n", hostname);
  		else printf("Incorrect dot-local hostname, address, or no mDNSResponder running on that machine\n");
  
  		if (NumAnswers)
  			{
  			// Because of the way we use lastsrc in ServicesCallback, we need to clear the cache to make sure we're getting fresh answers
  			mDNS *const m = &mDNSStorage;
  			mDNSu32 slot;
  			CacheGroup *cg;
  			CacheRecord *rr;
  			FORALL_CACHERECORDS(slot, cg, rr) mDNS_PurgeCacheResourceRecord(m, rr);
  			if (target.type == 0) target = hostaddr;		// Make sure the services query is targeted
  			DoQuery(&q, "_services._dns-sd._udp.local.", kDNSType_PTR, &target, ServicesCallback);
  			if (StopNow == 2) break;
  			}
  		}
  
  	mDNS_Close(&mDNSStorage);
  	return(0);
  
  usage:
  	fprintf(stderr, "Usage: %s <dot-local hostname> or <IPv4 address> or <IPv6 address> ...\n", progname);
  	return(-1);
  	}
  