Bonjour - Bonjour/Zerconf library

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Dirk-Willem van Gulik (NXP/mbed) / Mbed 2 deprecated Bonjour

Bonjour/Zerconf library

services/mDNS/mDNSResponder.cpp@1:59820ca5c83a, 2010-07-22 (annotated)

Committer:: dirkx
Date:: Thu Jul 22 00:08:38 2010 +0000
Revision:: 1:59820ca5c83a
Parent:: 0:355018f44c9f
Child:: 2:816cbd922d3e

Who changed what in which revision?

User	Revision	Line number	New contents of line
dirkx	0:355018f44c9f	1	/* Class: mDNSResponder
dirkx	0:355018f44c9f	2	* Copyright 1991, 2003, 2010 Dirk-Willem van Gulik <dirkx(at)apache(punto)org>
dirkx	0:355018f44c9f	3	*
dirkx	0:355018f44c9f	4	* License: Any BSD or ASF License.
dirkx	0:355018f44c9f	5	*
dirkx	0:355018f44c9f	6	* Rough and ready port of some mDNS code.
dirkx	0:355018f44c9f	7	*
dirkx	0:355018f44c9f	8	* Typical use is something like
dirkx	0:355018f44c9f	9	*
dirkx	0:355018f44c9f	10	* EthernetNetIf eth;
dirkx	0:355018f44c9f	11	* HTTPServer svr;
dirkx	0:355018f44c9f	12	* mDNSResponder mdns;
dirkx	0:355018f44c9f	13	*
dirkx	0:355018f44c9f	14	* int main()...
dirkx	0:355018f44c9f	15	*
dirkx	0:355018f44c9f	16	* // get internet
dirkx	0:355018f44c9f	17	* EthernetErr ethErr = eth.setup();
dirkx	0:355018f44c9f	18	* ... etc ..
dirkx	0:355018f44c9f	19	*
dirkx	0:355018f44c9f	20	* // set up some server
dirkx	0:355018f44c9f	21	* svr.addHandler<SimpleHandler>("/"); //Default handler
dirkx	0:355018f44c9f	22	* svr.bind(80); * *
dirkx	0:355018f44c9f	23
dirkx	0:355018f44c9f	24	* // Extract the IP address.
dirkx	0:355018f44c9f	25	* IpAddr ip = eth.getIp();
dirkx	0:355018f44c9f	26	* printf("mbed IP Address is %d.%d.%d.%d\r\n", ip[0], ip[1], ip[2], ip[3]);
dirkx	0:355018f44c9f	27	*
dirkx	0:355018f44c9f	28	* // Announce ourselves.
dirkx	1:59820ca5c83a	29	* mdns.announce(ip, "fred", "_http._tcp", 80, "The Little Server that Could", "path=/demo");
dirkx	0:355018f44c9f	30	*
dirkx	0:355018f44c9f	31	* while()... enter some run loop
dirkx	1:59820ca5c83a	32	* ...
dirkx	1:59820ca5c83a	33	*
dirkx	1:59820ca5c83a	34	* This will cause http://fred.local./demo to be announced as 'The Little Server that Could'.
dirkx	1:59820ca5c83a	35	*
dirkx	1:59820ca5c83a	36	* Or as another example: (http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt)
dirkx	1:59820ca5c83a	37	* and the various RFCs:
dirkx	0:355018f44c9f	38	*
dirkx	0:355018f44c9f	39	* mdns.announce(ip, "_ssh._tcp", 22, SSH to Serial Gateway", NULL);
dirkx	0:355018f44c9f	40	*
dirkx	0:355018f44c9f	41	* CAVEAT - a lot of the buffer overrun and copy checks
dirkx	0:355018f44c9f	42	* where removed; and this is not anywhere near
dirkx	0:355018f44c9f	43	* threadsafve or sane. Not for production use.
dirkx	0:355018f44c9f	44	*/
dirkx	0:355018f44c9f	45
dirkx	0:355018f44c9f	46	#include "mDNSResponder.h"
dirkx	0:355018f44c9f	47	#include <stdio.h>
dirkx	0:355018f44c9f	48
dirkx	0:355018f44c9f	49	// #define MCAST 192,168,1,71
dirkx	0:355018f44c9f	50
dirkx	0:355018f44c9f	51	mDNSResponder::mDNSResponder() : NetService(false),
dirkx	0:355018f44c9f	52	moi_txt(NULL), moi_port(0), moi_ip(0),
dirkx	0:355018f44c9f	53	moi_name(NULL), moi_proto(NULL),
dirkx	0:355018f44c9f	54	moi_local_proto(NULL), moi_local_name(NULL), moi_local_pglue(NULL),
dirkx	0:355018f44c9f	55	announcer()
dirkx	0:355018f44c9f	56	{
dirkx	0:355018f44c9f	57	// nothing yet...
dirkx	0:355018f44c9f	58	}
dirkx	0:355018f44c9f	59
dirkx	0:355018f44c9f	60	mDNSResponder::~mDNSResponder() {
dirkx	0:355018f44c9f	61	announcer.stop();
dirkx	0:355018f44c9f	62	close();
dirkx	0:355018f44c9f	63	}
dirkx	0:355018f44c9f	64
dirkx	1:59820ca5c83a	65	void mDNSResponder::announce(IpAddr ip, const char * ldn, const char * proto, uint16_t port, const char * name, char ** txt) {
dirkx	0:355018f44c9f	66	Host localhost(IpAddr(MCAST), MDNS_PORT, NULL /* fqdn */);
dirkx	0:355018f44c9f	67
dirkx	0:355018f44c9f	68	m_pUDPSocket = new UDPSocket;
dirkx	0:355018f44c9f	69	m_pUDPSocket->bind(localhost);
dirkx	0:355018f44c9f	70
dirkx	0:355018f44c9f	71	m_pUDPSocket->setOnEvent(this, &mDNSResponder::onUDPSocketEvent);
dirkx	0:355018f44c9f	72
dirkx	0:355018f44c9f	73	moi_port = port;
dirkx	0:355018f44c9f	74	moi_txt = txt;
dirkx	0:355018f44c9f	75	moi_ip = ip;
dirkx	0:355018f44c9f	76	moi_proto = proto;
dirkx	0:355018f44c9f	77	moi_name = name;
dirkx	0:355018f44c9f	78
dirkx	0:355018f44c9f	79	moi_local_proto = (char *)malloc(128);
dirkx	0:355018f44c9f	80	moi_local_name = (char *)malloc(128);
dirkx	0:355018f44c9f	81	moi_local_pglue = (char *)malloc(128);
dirkx	0:355018f44c9f	82
dirkx	0:355018f44c9f	83	#define LOCAL "local"
dirkx	0:355018f44c9f	84	snprintf(moi_local_proto,128,"%s.%s.", moi_proto, LOCAL);
dirkx	1:59820ca5c83a	85	snprintf(moi_local_name,128,"%s.%s.", ldn, LOCAL);
dirkx	0:355018f44c9f	86	snprintf(moi_local_pglue,128,"%s.%s.%s.", moi_name,moi_proto, LOCAL);
dirkx	0:355018f44c9f	87
dirkx	0:355018f44c9f	88	// Gratuis intro - and repeat such regularly..
dirkx	0:355018f44c9f	89	//
dirkx	0:355018f44c9f	90	mDNSResponder::sendReply(0, localhost);
dirkx	0:355018f44c9f	91	announcer.start();
dirkx	0:355018f44c9f	92	}
dirkx	0:355018f44c9f	93
dirkx	0:355018f44c9f	94	void mDNSResponder::close() {
dirkx	0:355018f44c9f	95	m_pUDPSocket->resetOnEvent();
dirkx	0:355018f44c9f	96	m_pUDPSocket->close();
dirkx	0:355018f44c9f	97	delete m_pUDPSocket;
dirkx	0:355018f44c9f	98	}
dirkx	0:355018f44c9f	99
dirkx	0:355018f44c9f	100
dirkx	0:355018f44c9f	101
dirkx	0:355018f44c9f	102	void mDNSResponder::poll() { //Called by NetServices
dirkx	0:355018f44c9f	103	if (announcer.read_ms() > 1000 * MDNS_INTERVAL) {
dirkx	0:355018f44c9f	104
dirkx	0:355018f44c9f	105	Host mch(IpAddr(MCAST), MDNS_PORT, NULL);
dirkx	0:355018f44c9f	106	mDNSResponder::sendReply(0, mch);
dirkx	0:355018f44c9f	107
dirkx	0:355018f44c9f	108	announcer.reset();
dirkx	0:355018f44c9f	109	}
dirkx	0:355018f44c9f	110	}
dirkx	0:355018f44c9f	111
dirkx	0:355018f44c9f	112	char * index(char * str, char c) {
dirkx	0:355018f44c9f	113	for(;str && *str;str++) {
dirkx	0:355018f44c9f	114	if (*str == c) return str;
dirkx	0:355018f44c9f	115	};
dirkx	0:355018f44c9f	116	return NULL;
dirkx	0:355018f44c9f	117	}
dirkx	0:355018f44c9f	118
dirkx	0:355018f44c9f	119	#ifndef THREADINGCOMPRESS
dirkx	0:355018f44c9f	120	#ifndef MAXCACHEDNSLABELS
dirkx	0:355018f44c9f	121	#define MAXCACHEDNSLABELS (10)
dirkx	0:355018f44c9f	122	#endif
dirkx	0:355018f44c9f	123	static int labelCacheCnt = 0;
dirkx	0:355018f44c9f	124	static uint16_t _cache_off[MAXCACHEDNSLABELS];
dirkx	0:355018f44c9f	125	static char * _cache_och[MAXCACHEDNSLABELS];
dirkx	0:355018f44c9f	126	static char * labelCacheOffset = 0;
dirkx	0:355018f44c9f	127
dirkx	0:355018f44c9f	128	void initLabelCache(char * off) {
dirkx	0:355018f44c9f	129	labelCacheOffset = off;
dirkx	0:355018f44c9f	130	labelCacheCnt = 0;
dirkx	0:355018f44c9f	131	memset(_cache_off,0, sizeof(_cache_off)); // Rely on min value to be 12
dirkx	0:355018f44c9f	132	};
dirkx	0:355018f44c9f	133
dirkx	0:355018f44c9f	134	uint16_t checkLabelCache(char * name) {
dirkx	0:355018f44c9f	135	for(int i=0; i < MAXCACHEDNSLABELS; i++)
dirkx	0:355018f44c9f	136	if (_cache_off[i] && !strcmp(_cache_och[i],name))
dirkx	0:355018f44c9f	137	return _cache_off[i];
dirkx	0:355018f44c9f	138	return 0;
dirkx	0:355018f44c9f	139	};
dirkx	0:355018f44c9f	140
dirkx	0:355018f44c9f	141	void addLabelCache(char * p, char * name) {
dirkx	0:355018f44c9f	142	_cache_off[labelCacheCnt] = p - labelCacheOffset;
dirkx	0:355018f44c9f	143	_cache_och[labelCacheCnt] = name;
dirkx	0:355018f44c9f	144
dirkx	0:355018f44c9f	145	labelCacheCnt++;
dirkx	1:59820ca5c83a	146	// we intentionally do not wack the first entries - as they are the most
dirkx	0:355018f44c9f	147	// likely ones to be used.
dirkx	0:355018f44c9f	148	if (labelCacheCnt>=MAXCACHEDNSLABELS)
dirkx	0:355018f44c9f	149	labelCacheCnt = MAXCACHEDNSLABELS / 3;
dirkx	0:355018f44c9f	150	};
dirkx	0:355018f44c9f	151	#else
dirkx	0:355018f44c9f	152	#define initLabelCache(x) {} /* Ignored */
dirkx	0:355018f44c9f	153	#define checkLabelCache(x) (0) /* never a hit */
dirkx	0:355018f44c9f	154	#define addLabelCache(x,y) {} /* Ignored */
dirkx	0:355018f44c9f	155	#endif
dirkx	0:355018f44c9f	156
dirkx	0:355018f44c9f	157	char * breakname(char p, char name) {
dirkx	0:355018f44c9f	158	int l = 0, de = 1;
dirkx	0:355018f44c9f	159	char * q;
dirkx	0:355018f44c9f	160	uint16_t off;
dirkx	0:355018f44c9f	161
dirkx	0:355018f44c9f	162	do {
dirkx	0:355018f44c9f	163	if (off = checkLabelCache(name)) {
dirkx	0:355018f44c9f	164	*p++ = 192 + (off >> 8);
dirkx	0:355018f44c9f	165	*p++ = (off & 0xFF);
dirkx	0:355018f44c9f	166	return p;
dirkx	0:355018f44c9f	167	} else {
dirkx	0:355018f44c9f	168	addLabelCache(p, name);
dirkx	0:355018f44c9f	169	};
dirkx	0:355018f44c9f	170
dirkx	0:355018f44c9f	171	q = index(name,'.');
dirkx	0:355018f44c9f	172	if (!q) {
dirkx	0:355018f44c9f	173	q = name + strlen(name);
dirkx	0:355018f44c9f	174	de = 0;
dirkx	0:355018f44c9f	175	};
dirkx	0:355018f44c9f	176	l = q - name;
dirkx	0:355018f44c9f	177	*p++ = l;
dirkx	0:355018f44c9f	178	memcpy(p, name, l);
dirkx	0:355018f44c9f	179	p+=l;
dirkx	0:355018f44c9f	180	name = q + 1;
dirkx	0:355018f44c9f	181	} while(l && *name);
dirkx	0:355018f44c9f	182
dirkx	0:355018f44c9f	183	// terminating root field if any (not the case for
dirkx	0:355018f44c9f	184	// things like TXTs).
dirkx	0:355018f44c9f	185	if (de) *p++ = 0;
dirkx	0:355018f44c9f	186	return p;
dirkx	0:355018f44c9f	187	}
dirkx	0:355018f44c9f	188
dirkx	0:355018f44c9f	189	char * mRR(char p, char name, uint16_t tpe, uint16_t cls, uint32_t ttl)
dirkx	0:355018f44c9f	190	{
dirkx	0:355018f44c9f	191	uint16_t i;
dirkx	0:355018f44c9f	192	uint32_t j;
dirkx	0:355018f44c9f	193
dirkx	0:355018f44c9f	194	p = breakname(p, name);
dirkx	0:355018f44c9f	195
dirkx	0:355018f44c9f	196	// NOTE: Cannot assume proper byte boundaries.
dirkx	0:355018f44c9f	197	//
dirkx	0:355018f44c9f	198	i = htons(tpe); // Type
dirkx	0:355018f44c9f	199	memcpy(p, &i, 2);
dirkx	0:355018f44c9f	200	p+=2;
dirkx	0:355018f44c9f	201
dirkx	0:355018f44c9f	202	i = htons(cls); // Class
dirkx	0:355018f44c9f	203	memcpy(p, &i, 2);
dirkx	0:355018f44c9f	204	p+=2;
dirkx	0:355018f44c9f	205
dirkx	0:355018f44c9f	206	j = htonl(ttl); // TTL (4 bytes)
dirkx	0:355018f44c9f	207	memcpy(p, &j, 4);
dirkx	0:355018f44c9f	208	p+=4;
dirkx	0:355018f44c9f	209
dirkx	0:355018f44c9f	210	return p;
dirkx	0:355018f44c9f	211	}
dirkx	0:355018f44c9f	212
dirkx	1:59820ca5c83a	213	char * mRRLABEL(char p, char name, uint16_t tpe, char ** rr) {
dirkx	0:355018f44c9f	214	uint16_t i;
dirkx	0:355018f44c9f	215
dirkx	0:355018f44c9f	216	p = mRR(p, name, tpe, 1, MDNS_TTL); // Type, IN, TTL
dirkx	0:355018f44c9f	217
dirkx	0:355018f44c9f	218	// RR String
dirkx	0:355018f44c9f	219	char * q = p + 2;
dirkx	1:59820ca5c83a	220
dirkx	1:59820ca5c83a	221	for(;*rr;rr++)
dirkx	1:59820ca5c83a	222	q = breakname(q, *rr);
dirkx	1:59820ca5c83a	223
dirkx	0:355018f44c9f	224	i = htons(q - p - 2); // RDLEN
dirkx	0:355018f44c9f	225	memcpy(p, &i, 2);
dirkx	0:355018f44c9f	226	return q;
dirkx	0:355018f44c9f	227	}
dirkx	0:355018f44c9f	228
dirkx	1:59820ca5c83a	229	char * mPTR(char p, char name, char * r) {
dirkx	1:59820ca5c83a	230	char *rr[] = { r, NULL };
dirkx	1:59820ca5c83a	231	return mRRLABEL(p, name, 12 /* PTR */, rr );
dirkx	0:355018f44c9f	232	}
dirkx	0:355018f44c9f	233
dirkx	1:59820ca5c83a	234	char * mTXT(char p, char name, char ** rr) {
dirkx	0:355018f44c9f	235	return mRRLABEL(p, name, 16 /* TXT */, rr);
dirkx	0:355018f44c9f	236	}
dirkx	0:355018f44c9f	237
dirkx	0:355018f44c9f	238	char * mARR(char p, char name, IpAddr ip) {
dirkx	0:355018f44c9f	239	uint16_t i;
dirkx	0:355018f44c9f	240
dirkx	0:355018f44c9f	241	p = mRR(p, name, 1, 1, MDNS_TTL ); // A, IN
dirkx	0:355018f44c9f	242
dirkx	0:355018f44c9f	243	i = htons(4); // RDLEN - we're just doing a single IPv4 address - our primary link ?
dirkx	0:355018f44c9f	244	memcpy(p, &i, 2);
dirkx	0:355018f44c9f	245
dirkx	0:355018f44c9f	246	// IP already in network order.
dirkx	0:355018f44c9f	247	memcpy(p+2, &ip, 4);
dirkx	0:355018f44c9f	248
dirkx	0:355018f44c9f	249	return p + 2 + 4;
dirkx	0:355018f44c9f	250	}
dirkx	0:355018f44c9f	251
dirkx	0:355018f44c9f	252	char * mSRV(char p, char name, uint16_t port, char * rr) {
dirkx	0:355018f44c9f	253	uint16_t i;
dirkx	0:355018f44c9f	254	char * q;
dirkx	0:355018f44c9f	255
dirkx	0:355018f44c9f	256	p = mRR(p, name, 33, 1, MDNS_TTL); // SRV, IN
dirkx	0:355018f44c9f	257
dirkx	0:355018f44c9f	258	// Keep space for RDLEN
dirkx	0:355018f44c9f	259	q = p; p+=2;
dirkx	0:355018f44c9f	260
dirkx	0:355018f44c9f	261	i = htons(1); // Priority
dirkx	0:355018f44c9f	262	memcpy(p, &i, 2); p+=2;
dirkx	0:355018f44c9f	263
dirkx	0:355018f44c9f	264	i = htons(0); // Weight (see rfc2782)
dirkx	0:355018f44c9f	265	memcpy(p, &i, 2); p+=2;
dirkx	0:355018f44c9f	266
dirkx	0:355018f44c9f	267	i = htons(port); // Port
dirkx	0:355018f44c9f	268	memcpy(p, &i, 2); p+=2;
dirkx	0:355018f44c9f	269
dirkx	0:355018f44c9f	270	p = breakname(p, rr);
dirkx	0:355018f44c9f	271
dirkx	0:355018f44c9f	272	i = htons(p - q - 2); // RDLEN
dirkx	0:355018f44c9f	273	memcpy(q, &i, 2);
dirkx	0:355018f44c9f	274
dirkx	0:355018f44c9f	275	return p;
dirkx	0:355018f44c9f	276	}
dirkx	0:355018f44c9f	277
dirkx	0:355018f44c9f	278	char * qANY(char p, char name, uint16_t tpe, uint16_t cls) {
dirkx	0:355018f44c9f	279	uint16_t i;
dirkx	0:355018f44c9f	280	p = breakname(p, name); // QNAME
dirkx	0:355018f44c9f	281
dirkx	0:355018f44c9f	282	i = htons(tpe); // QTYPE
dirkx	0:355018f44c9f	283	memcpy(p, &i, 2); p+=2;
dirkx	0:355018f44c9f	284
dirkx	0:355018f44c9f	285	i = htons(cls); // QCLASS
dirkx	0:355018f44c9f	286	memcpy(p, &i, 2); p+=2;
dirkx	0:355018f44c9f	287
dirkx	0:355018f44c9f	288	return p;
dirkx	0:355018f44c9f	289	}
dirkx	0:355018f44c9f	290
dirkx	0:355018f44c9f	291	char * qPTR(char p, char name) {
dirkx	0:355018f44c9f	292	return qANY(p,name,12 /* PTR */,1);
dirkx	0:355018f44c9f	293	}
dirkx	0:355018f44c9f	294
dirkx	0:355018f44c9f	295
dirkx	0:355018f44c9f	296	void mDNSResponder::sendReply(uint16_t tid, Host dst) {
dirkx	0:355018f44c9f	297	// sent a reply - basically a precooked A/PTR/SRV with the TransactionID
dirkx	0:355018f44c9f	298	// and my URI squeezed in.
dirkx	0:355018f44c9f	299	char out[ 1500 ], *p;
dirkx	0:355018f44c9f	300	DNSPacket * op = (DNSPacket *) out;
dirkx	0:355018f44c9f	301
dirkx	0:355018f44c9f	302	initLabelCache(out); // Offsets are relative to the ID header.
dirkx	0:355018f44c9f	303
dirkx	0:355018f44c9f	304	op->tid = ntohs(tid);
dirkx	0:355018f44c9f	305	op->flags = ntohs(0x8000U); // Answer
dirkx	0:355018f44c9f	306	op->question_count = ntohs(1); // Courtesy copy of the question.
dirkx	0:355018f44c9f	307	op->answer_count = ntohs(1); // The PTR record asked for
dirkx	0:355018f44c9f	308	op->a_count = ntohs(0);
dirkx	0:355018f44c9f	309
dirkx	0:355018f44c9f	310	// The 2 or 3 extra records (A, SRV and optional TXT) we know will be needed next
dirkx	0:355018f44c9f	311	op->aa_count = ntohs(moi_txt ? 3 : 2);
dirkx	0:355018f44c9f	312
dirkx	0:355018f44c9f	313	p = out + 12;
dirkx	0:355018f44c9f	314
dirkx	0:355018f44c9f	315	p = qPTR(p,moi_local_proto);
dirkx	0:355018f44c9f	316	p = mPTR(p,moi_local_proto, moi_local_pglue);
dirkx	0:355018f44c9f	317	p = mSRV(p,moi_local_pglue,80, moi_local_name);
dirkx	1:59820ca5c83a	318	if (moi_txt && * moi_txt)
dirkx	1:59820ca5c83a	319	p = mTXT(p,moi_local_pglue,moi_txt);
dirkx	0:355018f44c9f	320	p = mARR(p,moi_local_name,moi_ip); // fill out my own IP address.
dirkx	0:355018f44c9f	321
dirkx	0:355018f44c9f	322	m_pUDPSocket->sendto(out,p-out,&dst);
dirkx	0:355018f44c9f	323	}
dirkx	0:355018f44c9f	324
dirkx	0:355018f44c9f	325	void mDNSResponder::onUDPSocketEvent(UDPSocketEvent e) {
dirkx	0:355018f44c9f	326	char udp[ 1500 ];
dirkx	0:355018f44c9f	327	Host from;
dirkx	0:355018f44c9f	328	int len;
dirkx	0:355018f44c9f	329
dirkx	0:355018f44c9f	330	switch (e) {
dirkx	0:355018f44c9f	331	case UDPSOCKET_READABLE: //The only event for now
dirkx	0:355018f44c9f	332	// parse through the packet; find any PTR requests
dirkx	0:355018f44c9f	333	// and respond to any for _http._tcp._local.
dirkx	0:355018f44c9f	334	while ( len = m_pUDPSocket->recvfrom( (char*)&udp, sizeof(udp), &from )) {
dirkx	0:355018f44c9f	335	DNSPacket * dp = (DNSPacket *) udp;
dirkx	0:355018f44c9f	336	unsigned int tid = ntohs(dp->tid);
dirkx	0:355018f44c9f	337	unsigned int flags = ntohs(dp->flags);
dirkx	0:355018f44c9f	338	unsigned int nQ = ntohs(dp->question_count);
dirkx	0:355018f44c9f	339	unsigned int nA = ntohs(dp->answer_count);
dirkx	0:355018f44c9f	340
dirkx	0:355018f44c9f	341	if (flags & 2 != 0 \|\| nQ == 0)
dirkx	0:355018f44c9f	342	continue; // we only want questions
dirkx	0:355018f44c9f	343
dirkx	0:355018f44c9f	344	#define MAXDEPTH 64
dirkx	0:355018f44c9f	345	#define MAXRR 192 /* including dot */
dirkx	1:59820ca5c83a	346
dirkx	0:355018f44c9f	347	// assume nQ zero terminated fields followed by Qtype & Qclass
dirkx	0:355018f44c9f	348	char * p = udp + 12;
dirkx	0:355018f44c9f	349	for (int i = 0; i < nQ; i++) {
dirkx	0:355018f44c9f	350	char buff[ MAXDEPTH * MAXRR ], * ep = buff;
dirkx	0:355018f44c9f	351	int depth = 0;
dirkx	0:355018f44c9f	352	int l;
dirkx	0:355018f44c9f	353	char * q = 0;
dirkx	0:355018f44c9f	354
dirkx	0:355018f44c9f	355	do {
dirkx	0:355018f44c9f	356	while (((l = *p++) < 192) && (l > 0)) {
dirkx	0:355018f44c9f	357	if (p + l >= udp + len) {
dirkx	0:355018f44c9f	358	printf("RR longer than packet\r\n");
dirkx	0:355018f44c9f	359	return;
dirkx	0:355018f44c9f	360	};
dirkx	0:355018f44c9f	361
dirkx	0:355018f44c9f	362	memcpy(ep,p,l);
dirkx	0:355018f44c9f	363	ep[l]='.';
dirkx	0:355018f44c9f	364	ep += l + 1;
dirkx	0:355018f44c9f	365	// printf("%d:%s.", p-udp-12,buff);
dirkx	0:355018f44c9f	366	p += l;
dirkx	0:355018f44c9f	367	};
dirkx	0:355018f44c9f	368	if (l >= 192) {
dirkx	0:355018f44c9f	369	// construct an offset pointer by wiping the top 1 bits
dirkx	0:355018f44c9f	370	// and then getting the remaining 8 bytes to make 14.
dirkx	0:355018f44c9f	371	l -= 192;
dirkx	0:355018f44c9f	372	l = l << 8;
dirkx	0:355018f44c9f	373	l += *p++;
dirkx	0:355018f44c9f	374	// rescue our reference; as we've not gotten the Qt's yet.
dirkx	0:355018f44c9f	375	if (!q) q = p;
dirkx	0:355018f44c9f	376
dirkx	0:355018f44c9f	377	// printf(" [->%d] ",l);
dirkx	0:355018f44c9f	378	p = udp + l;
dirkx	0:355018f44c9f	379
dirkx	0:355018f44c9f	380	if (p >= udp + len \|\| p < udp + 12) {
dirkx	0:355018f44c9f	381	printf("Pointer to wrong place\r\n");
dirkx	0:355018f44c9f	382	return;
dirkx	0:355018f44c9f	383	};
dirkx	0:355018f44c9f	384	};
dirkx	0:355018f44c9f	385	if (depth++ >= MAXDEPTH) {
dirkx	0:355018f44c9f	386	printf("Too deep\r\n");
dirkx	0:355018f44c9f	387	return;
dirkx	0:355018f44c9f	388	};
dirkx	0:355018f44c9f	389	} while (l);
dirkx	0:355018f44c9f	390	*ep = 0;
dirkx	0:355018f44c9f	391	// in case no compression was used at all.
dirkx	0:355018f44c9f	392	if (!q) q = p;
dirkx	0:355018f44c9f	393
dirkx	0:355018f44c9f	394	unsigned int Qt = htons(q[0] + q[1]*256);
dirkx	0:355018f44c9f	395	unsigned int Qc = htons(q[2] + q[3]*256);
dirkx	0:355018f44c9f	396	p = q + 4;
dirkx	1:59820ca5c83a	397
dirkx	1:59820ca5c83a	398	printf("Q for %s\r\n", buff);
dirkx	0:355018f44c9f	399	// We want PTR records on the INternet of our type
dirkx	0:355018f44c9f	400	if ((Qt == 12) && (Qc == 1) && !(strcmp(buff,moi_local_proto)))
dirkx	0:355018f44c9f	401	sendReply(tid,from);
dirkx	0:355018f44c9f	402	};
dirkx	0:355018f44c9f	403	}
dirkx	0:355018f44c9f	404	break;
dirkx	0:355018f44c9f	405	}
dirkx	0:355018f44c9f	406	}
dirkx	0:355018f44c9f	407
dirkx	0:355018f44c9f	408

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	21 Jul 2010
Imports:	99
Forks:	0
Commits:	6
Dependents:	0
Dependencies:	1
Followers:	8

services/mDNS/mDNSResponder.cpp@1:59820ca5c83a, 2010-07-22 (annotated)

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