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DNSServer drop dynamically allocated member structs
DNSHeader and DNSQuestion structs could be created on stack no need to keep it as obj members
1 parent d8b8993 commit e50dfef

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2 files changed

+49
-76
lines changed

2 files changed

+49
-76
lines changed

‎libraries/DNSServer/src/DNSServer.cpp

Lines changed: 44 additions & 69 deletions
Original file line numberDiff line numberDiff line change
@@ -9,23 +9,9 @@
99
#define DEBUG_OUTPUT Serial
1010
#endif
1111

12-
DNSServer::DNSServer() : _port(0), _ttl(htonl(DNS_DEFAULT_TTL)), _errorReplyCode(DNSReplyCode::NonExistentDomain)
13-
{
14-
_dnsHeader = new DNSHeader();
15-
_dnsQuestion = new DNSQuestion();
16-
}
12+
DNSServer::DNSServer() : _port(0), _ttl(htonl(DNS_DEFAULT_TTL)), _errorReplyCode(DNSReplyCode::NonExistentDomain){}
1713

18-
DNSServer::~DNSServer()
19-
{
20-
if (_dnsHeader) {
21-
delete _dnsHeader;
22-
_dnsHeader = nullptr;
23-
}
24-
if (_dnsQuestion) {
25-
delete _dnsQuestion;
26-
_dnsQuestion = nullptr;
27-
}
28-
}
14+
DNSServer::~DNSServer(){}
2915

3016
bool DNSServer::start(const uint16_t &port, const String &domainName,
3117
const IPAddress &resolvedIP)
@@ -37,6 +23,7 @@ bool DNSServer::start(const uint16_t &port, const String &domainName,
3723
_resolvedIP[2] = resolvedIP[2];
3824
_resolvedIP[3] = resolvedIP[3];
3925
downcaseAndRemoveWwwPrefix(_domainName);
26+
_udp.close();
4027
_udp.onPacket([this](AsyncUDPPacket& pkt){ this->_handleUDP(pkt); });
4128
return _udp.listen(_port);
4229
}
@@ -64,70 +51,58 @@ void DNSServer::downcaseAndRemoveWwwPrefix(String &domainName)
6451

6552
void DNSServer::_handleUDP(AsyncUDPPacket& pkt)
6653
{
67-
size_t _currentPacketSize = pkt.length();
68-
if (_currentPacketSize < DNS_HEADER_SIZE) return;
54+
size_t currentPacketSize = pkt.length();
55+
if (currentPacketSize < DNS_HEADER_SIZE) return;
6956

7057
// get DNS header (beginning of message)
71-
memcpy( _dnsHeader, pkt.data(), DNS_HEADER_SIZE );
72-
if (_dnsHeader->QR != DNS_QR_QUERY) return; // ignore non-query mesages
58+
DNSHeader dnsHeader;
59+
DNSQuestion dnsQuestion;
60+
memcpy( &dnsHeader, pkt.data(), DNS_HEADER_SIZE );
61+
if (dnsHeader.QR != DNS_QR_QUERY) return; // ignore non-query mesages
7362

74-
if ( requestIncludesOnlyOneQuestion() )
63+
if ( requestIncludesOnlyOneQuestion(dnsHeader) )
7564
{
65+
/*
66+
// The QName has a variable length, maximum 255 bytes and is comprised of multiple labels.
67+
// Each label contains a byte to describe its length and the label itself. The list of
68+
// labels terminates with a zero-valued byte. In "github.com", we have two labels "github" & "com"
69+
*/
7670
char * enoflbls = strchr((const char*)pkt.data() + DNS_HEADER_SIZE, 0); // find end_of_label marker
7771
++enoflbls; // include null terminator
78-
_dnsQuestion->QName = pkt.data() + DNS_HEADER_SIZE; // we can reference labels from the request
79-
_dnsQuestion->QNameLength = enoflbls - (char*)pkt.data() - DNS_HEADER_SIZE;
72+
dnsQuestion.QName = pkt.data() + DNS_HEADER_SIZE; // we can reference labels from the request
73+
dnsQuestion.QNameLength = enoflbls - (char*)pkt.data() - DNS_HEADER_SIZE;
8074
/*
8175
check if we aint going out of pkt bounds
8276
proper dns req should have label terminator at least 4 bytes before end of packet
8377
*/
84-
if (_dnsQuestion->QNameLength > _currentPacketSize - sizeof(_dnsQuestion->QType) - sizeof(_dnsQuestion->QClass)) return; // malformed packet
78+
if (dnsQuestion.QNameLength > currentPacketSize - sizeof(dnsQuestion.QType) - sizeof(dnsQuestion.QClass)) return; // malformed packet
8579

8680
// Copy the QType and QClass
87-
memcpy( &_dnsQuestion->QType, enoflbls, sizeof(_dnsQuestion->QType) );
88-
memcpy( &_dnsQuestion->QClass, enoflbls + sizeof(_dnsQuestion->QType), sizeof(_dnsQuestion->QClass) );
89-
90-
/*
91-
// The QName has a variable length, maximum 255 bytes and is comprised of multiple labels.
92-
// Each label contains a byte to describe its length and the label itself. The list of
93-
// labels terminates with a zero-valued byte. In "github.com", we have two labels "github" & "com"
94-
// Iterate through the labels and copy them as they come into a single buffer (for simplicity's sake)
95-
_dnsQuestion->QNameLength = 0 ;
96-
while ( _buffer[ DNS_HEADER_SIZE + _dnsQuestion->QNameLength ] != 0 )
97-
{
98-
memcpy( (void*) &_dnsQuestion->QName[_dnsQuestion->QNameLength], (void*) &_buffer[DNS_HEADER_SIZE + _dnsQuestion->QNameLength], _buffer[DNS_HEADER_SIZE + _dnsQuestion->QNameLength] + 1 ) ;
99-
_dnsQuestion->QNameLength += _buffer[DNS_HEADER_SIZE + _dnsQuestion->QNameLength] + 1 ;
100-
}
101-
_dnsQuestion->QName[_dnsQuestion->QNameLength] = 0 ;
102-
_dnsQuestion->QNameLength++ ;
103-
104-
// Copy the QType and QClass
105-
memcpy( &_dnsQuestion->QType, (void*) &_buffer[DNS_HEADER_SIZE + _dnsQuestion->QNameLength], sizeof(_dnsQuestion->QType) ) ;
106-
memcpy( &_dnsQuestion->QClass, (void*) &_buffer[DNS_HEADER_SIZE + _dnsQuestion->QNameLength + sizeof(_dnsQuestion->QType)], sizeof(_dnsQuestion->QClass) ) ;
107-
*/
81+
memcpy( &dnsQuestion.QType, enoflbls, sizeof(dnsQuestion.QType) );
82+
memcpy( &dnsQuestion.QClass, enoflbls + sizeof(dnsQuestion.QType), sizeof(dnsQuestion.QClass) );
10883
}
109-
84+
11085
// will reply with IP only to "*" or if doman matches without www. subdomain
111-
if (_dnsHeader->OPCode == DNS_OPCODE_QUERY &&
112-
requestIncludesOnlyOneQuestion() &&
86+
if (dnsHeader.OPCode == DNS_OPCODE_QUERY &&
87+
requestIncludesOnlyOneQuestion(dnsHeader) &&
11388
(_domainName == "*" ||
114-
getDomainNameWithoutWwwPrefix((const char*)pkt.data() + DNS_HEADER_SIZE, _dnsQuestion->QNameLength) == _domainName)
89+
getDomainNameWithoutWwwPrefix((const char*)pkt.data() + DNS_HEADER_SIZE, dnsQuestion.QNameLength) == _domainName)
11590
)
11691
{
117-
replyWithIP(pkt);
92+
replyWithIP(pkt, dnsHeader, dnsQuestion);
11893
return;
11994
}
12095

12196
// otherwise reply with custom code
122-
replyWithCustomCode(pkt);
97+
replyWithCustomCode(pkt, dnsHeader);
12398
}
12499

125-
bool DNSServer::requestIncludesOnlyOneQuestion()
100+
bool DNSServer::requestIncludesOnlyOneQuestion(DNSHeader& dnsHeader)
126101
{
127-
return ntohs(_dnsHeader->QDCount) == 1 &&
128-
_dnsHeader->ANCount == 0 &&
129-
_dnsHeader->NSCount == 0 &&
130-
_dnsHeader->ARCount == 0;
102+
return ntohs(dnsHeader.QDCount) == 1 &&
103+
dnsHeader.ANCount == 0 &&
104+
dnsHeader.NSCount == 0 &&
105+
dnsHeader.ARCount == 0;
131106
}
132107

133108

@@ -164,20 +139,20 @@ String DNSServer::getDomainNameWithoutWwwPrefix(const char* start, size_t len)
164139
}
165140
}
166141

167-
void DNSServer::replyWithIP(AsyncUDPPacket& req)
142+
void DNSServer::replyWithIP(AsyncUDPPacket& req, DNSHeader& dnsHeader, DNSQuestion& dnsQuestion)
168143
{
169144
AsyncUDPMessage rpl;
170145

171146
// Change the type of message to a response and set the number of answers equal to
172147
// the number of questions in the header
173-
_dnsHeader->QR = DNS_QR_RESPONSE;
174-
_dnsHeader->ANCount = _dnsHeader->QDCount;
175-
rpl.write( (unsigned char*) _dnsHeader, DNS_HEADER_SIZE ) ;
148+
dnsHeader.QR = DNS_QR_RESPONSE;
149+
dnsHeader.ANCount = dnsHeader.QDCount;
150+
rpl.write( (unsigned char*) &dnsHeader, DNS_HEADER_SIZE ) ;
176151

177152
// Write the question
178-
rpl.write(_dnsQuestion->QName, _dnsQuestion->QNameLength) ;
179-
rpl.write( (uint8_t*) &_dnsQuestion->QType, 2 ) ;
180-
rpl.write( (uint8_t*) &_dnsQuestion->QClass, 2 ) ;
153+
rpl.write(dnsQuestion.QName, dnsQuestion.QNameLength) ;
154+
rpl.write( (uint8_t*) &dnsQuestion.QType, 2 ) ;
155+
rpl.write( (uint8_t*) &dnsQuestion.QClass, 2 ) ;
181156

182157
// Write the answer
183158
// Use DNS name compression : instead of repeating the name in this RNAME occurence,
@@ -199,17 +174,17 @@ void DNSServer::replyWithIP(AsyncUDPPacket& req)
199174

200175
#ifdef DEBUG_ESP_DNS
201176
DEBUG_OUTPUT.printf("DNS responds: %s for %s\n",
202-
IPAddress(_resolvedIP).toString().c_str(), getDomainNameWithoutWwwPrefix((const char*)rpl.data() + DNS_HEADER_SIZE, _dnsQuestion->QNameLength).c_str() );
177+
IPAddress(_resolvedIP).toString().c_str(), getDomainNameWithoutWwwPrefix((const char*)rpl.data() + DNS_HEADER_SIZE, dnsQuestion.QNameLength).c_str() );
203178
#endif
204179
}
205180

206-
void DNSServer::replyWithCustomCode(AsyncUDPPacket& req)
181+
void DNSServer::replyWithCustomCode(AsyncUDPPacket& req, DNSHeader& dnsHeader)
207182
{
208-
_dnsHeader->QR = DNS_QR_RESPONSE;
209-
_dnsHeader->RCode = (uint16_t)_errorReplyCode;
210-
_dnsHeader->QDCount = 0;
183+
dnsHeader.QR = DNS_QR_RESPONSE;
184+
dnsHeader.RCode = (uint16_t)_errorReplyCode;
185+
dnsHeader.QDCount = 0;
211186

212187
AsyncUDPMessage rpl(sizeof(DNSHeader));
213-
rpl.write((unsigned char*)_dnsHeader, sizeof(DNSHeader));
188+
rpl.write((unsigned char*)&dnsHeader, sizeof(DNSHeader));
214189
_udp.sendTo(rpl, req.remoteIP(), req.remotePort());
215190
}

‎libraries/DNSServer/src/DNSServer.h

Lines changed: 5 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -59,9 +59,9 @@ struct DNSHeader
5959
uint16_t Flags;
6060
};
6161
uint16_t QDCount; // number of question entries
62-
uint16_t ANCount; // number of answer entries
62+
uint16_t ANCount; // number of ANswer entries
6363
uint16_t NSCount; // number of authority entries
64-
uint16_t ARCount; // number of resource entries
64+
uint16_t ARCount; // number of Additional Resource entries
6565
};
6666

6767
struct DNSQuestion
@@ -95,8 +95,6 @@ class DNSServer
9595
DNSReplyCode _errorReplyCode;
9696
String _domainName;
9797
unsigned char _resolvedIP[4];
98-
DNSHeader* _dnsHeader;
99-
DNSQuestion* _dnsQuestion ;
10098

10199

102100
void downcaseAndRemoveWwwPrefix(String &domainName);
@@ -110,9 +108,9 @@ class DNSServer
110108
* @return String
111109
*/
112110
String getDomainNameWithoutWwwPrefix(const char* start, size_t len);
113-
bool requestIncludesOnlyOneQuestion();
114-
void replyWithIP(AsyncUDPPacket& req);
115-
void replyWithCustomCode(AsyncUDPPacket& req);
111+
inline bool requestIncludesOnlyOneQuestion(DNSHeader& dnsHeader);
112+
void replyWithIP(AsyncUDPPacket& req, DNSHeader& dnsHeader, DNSQuestion& dnsQuestion);
113+
inline void replyWithCustomCode(AsyncUDPPacket& req, DNSHeader& dnsHeader);
116114
void _handleUDP(AsyncUDPPacket& pkt);
117115
};
118116
#endif

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