publish libraries to avoid users to have to download them one by one

2018-03-04 13:47:37 +01:00
1 parent 93c075e880
commit f0546fab8c
@@ -0,0 +1,244 @@
+#ifndef MDNS_H
+#define MDNS_H
+
+#include <Arduino.h>
+#include <ESP8266WiFi.h>
+#include <WiFiUdp.h>
+
+#define DEBUG_STATISTICS      // Record how many incoming packets fitted into data_buffer.
+//#define DEBUG_OUTPUT          // Send packet summaries to Serial.
+//#define DEBUG_RAW             // Send HEX ans ASCII encoded raw packet to Serial.
+
+
+#define MDNS_TYPE_A     0x0001
+#define MDNS_TYPE_PTR   0x000C
+#define MDNS_TYPE_HINFO 0x000D
+#define MDNS_TYPE_TXT   0x0010
+#define MDNS_TYPE_AAAA  0x001C
+#define MDNS_TYPE_SRV   0x0021
+
+#define MDNS_TARGET_PORT 5353
+#define MDNS_SOURCE_PORT 5353
+#define MDNS_TTL 255
+
+// Make this as big as memory limitations allow.
+// This default value can be overridden using the max_packet_size_ parameter of
+// MDns().
+#define MAX_PACKET_SIZE 1024
+
+// The mDNS spec says this should never be more than 256 (including trailing '\0').
+#define MAX_MDNS_NAME_LEN 256  
+
+namespace mdns{
+
+// A single mDNS Query.
+typedef struct Query{
+#ifdef DEBUG_OUTPUT
+  unsigned int buffer_pointer;            // Position of Answer in packet. (Used for debugging only.)
+#endif
+  char qname_buffer[MAX_MDNS_NAME_LEN];   // Question Name: Contains the object, domain or zone name.
+  unsigned int qtype;                     // Question Type: Type of question being asked by client.
+  unsigned int qclass;                    // Question Class: Normally the value 1 for Internet (“IN”)
+  bool unicast_response;                  // 
+  bool valid;                             // False if problems were encountered decoding packet.
+
+  void Display() const;                   // Display a summary of this Answer on Serial port.
+} Query;
+
+// A single mDNS Answer.
+typedef struct Answer{
+#ifdef DEBUG_OUTPUT
+  unsigned int buffer_pointer;          // Position of Answer in packet. (Used for debugging only.)
+#endif
+  char name_buffer[MAX_MDNS_NAME_LEN];  // object, domain or zone name.
+  char rdata_buffer[MAX_MDNS_NAME_LEN]; // The data portion of the resource record.
+  unsigned int rrtype;                  // ResourceRecord Type.
+  unsigned int rrclass;                 // ResourceRecord Class: Normally the value 1 for Internet (“IN”)
+  unsigned long int rrttl;              // ResourceRecord Time To Live: Number of seconds ths should be remembered.
+  bool rrset;                           // Flush cache of records matching this name.
+  bool valid;                           // False if problems were encountered decoding packet.
+
+  void Display() const ;                // Display a summary of this Answer on Serial port.
+} Answer;
+
+class MDns {
+ private:
+ public:
+  // Simple constructor does not fire any callbacks on incoming data.
+  // Default incoming data_buffer size is used.
+  MDns() : MDns(NULL, NULL, NULL, MAX_PACKET_SIZE) {}
+
+  // Simple constructor does not fire any callbacks on incoming data.
+  // Args:
+  //   max_packet_size_ : Set the data_buffer size allocated to store incoming packets.
+  MDns(int max_packet_size_) : MDns(NULL, NULL, NULL, max_packet_size_) {}
+  
+  // Constructor takes callbacks which fire when mDNS data arrives.
+  // Args:
+  //   p_packet_function : Callback fires for every mDNS packet that arrives.
+  //   p_query_function : Callback fires for every mDNS Query that arrives as part of a packet.
+  //   p_answer_function : Callback fires for every mDNS Answer that arrives as part of a packet.
+  MDns(std::function<void(const MDns*)> p_packet_function, 
+       std::function<void(const Query*)> p_query_function, 
+       std::function<void(const Answer*)> p_answer_function) :
+    MDns(p_packet_function, p_query_function, p_answer_function, MAX_PACKET_SIZE) { }
+
+  // Constructor takes callbacks which fire when mDNS data arrives.
+  // Args:
+  //   p_packet_function : Callback fires for every mDNS packet that arrives.
+  //   p_query_function : Callback fires for every mDNS Query that arrives as part of a packet.
+  //   p_answer_function : Callback fires for every mDNS Answer that arrives as part of a packet.
+  //   max_packet_size_ : Set the data_buffer size allocated to store incoming packets.
+  MDns(std::function<void(const MDns*)> p_packet_function, 
+       std::function<void(const Query*)> p_query_function, 
+       std::function<void(const Answer*)> p_answer_function,
+       int max_packet_size_) :
+#ifdef DEBUG_STATISTICS
+       buffer_size_fail(0),
+       largest_packet_seen(0),
+       packet_count(0),
+#endif
+       p_packet_function_(p_packet_function),
+       p_query_function_(p_query_function),
+       p_answer_function_(p_answer_function),
+       buffer_pointer(0),
+       data_buffer(new byte[max_packet_size_]),
+       max_packet_size(max_packet_size_)
+       { 
+         this->startUdpMulticast();
+       };
+
+  // Constructor can be passed the buffer to hold the mDNS data.
+  // This way the potentially large buffer can be shared with other processes.
+  // Args:
+  //   p_packet_function : Callback fires for every mDNS packet that arrives.
+  //   p_query_function : Callback fires for every mDNS Query that arrives as part of a packet.
+  //   p_answer_function : Callback fires for every mDNS Answer that arrives as part of a packet.
+  //   max_packet_size_ : Set the data_buffer size allocated to store incoming packets.
+  MDns(std::function<void(const MDns*)> p_packet_function, 
+       std::function<void(const Query*)> p_query_function,
+       std::function<void(const Answer*)> p_answer_function,
+       byte* data_buffer_,
+       int max_packet_size_) :
+#ifdef DEBUG_STATISTICS
+       buffer_size_fail(0),
+       largest_packet_seen(0),
+       packet_count(0),
+#endif
+       p_packet_function_(p_packet_function),
+       p_query_function_(p_query_function),
+       p_answer_function_(p_answer_function),
+       buffer_pointer(0),
+       data_buffer(data_buffer_),
+       max_packet_size(max_packet_size_)
+       { 
+         this->startUdpMulticast();
+       };
+
+  ~MDns();
+
+  // Call this regularly to check for an incoming packet.
+  bool loop();
+  // Deprecated. Use loop() instead.
+  bool Check(){
+    return loop();
+  }
+
+  // Send this MDns packet.
+  void Send() const;
+
+  // Resets everything to represent an empty packet.
+  // Do this before building a packet for sending.
+  void Clear();
+
+  // Add a query to packet prior to sending.
+  // May only be done before any Answers have been added.
+  bool AddQuery(const Query& query);
+
+  // Add an answer to packet prior to sending.
+  bool AddAnswer(const Answer& answer);
+  
+  // Display a summary of the packet on Serial port.
+  void Display() const;
+  
+  // Display the raw packet in HEX and ASCII.
+  void DisplayRawPacket() const;
+ 
+#ifdef DEBUG_STATISTICS
+  // Counter gets increased every time an incoming mDNS packet arrives that does
+  // not fit in the data_buffer.
+  unsigned int buffer_size_fail;
+
+  // Track the largest mDNS packet that has arrived.
+  // Useful for knowing what size to make data_buffer.
+  unsigned int largest_packet_seen;
+
+  // How many mDNS packets have arrived so far.
+  unsigned int packet_count;
+#endif
+ private:
+  // Initializes udp multicast
+  void startUdpMulticast();
+
+  void Parse_Query(Query& query);
+  void Parse_Answer(Answer& answer);
+  unsigned int PopulateName(const char* name_buffer);
+  void PopulateAnswerResult(Answer* answer);
+
+  // Pointer to function that gets called for every incoming mDNS packet.
+  std::function<void(const MDns*)> p_packet_function_;
+
+  // Pointer to function that gets called for every incoming query.
+  std::function<void(const Query*)> p_query_function_;
+
+  // Pointer to function that gets called for every incoming answer.
+  std::function<void(const Answer*)> p_answer_function_;
+
+  // Position in data_buffer while processing packet.
+  unsigned int buffer_pointer;
+
+  // Buffer containing mDNS packet.
+  byte* data_buffer;
+
+  // Buffer size for incoming MDns packet.
+  unsigned int max_packet_size;
+
+  // Size of mDNS packet.
+  unsigned int data_size;
+
+  // Query or Answer
+  bool type;
+
+  // Whether more follows in another packet.
+  bool truncated;
+
+  // Number of Qeries in the packet.
+  unsigned int query_count;
+  
+  // Number of Answers in the packet.
+  unsigned int answer_count;
+  
+  unsigned int ns_count;
+  unsigned int ar_count;
+};
+
+
+// Display a byte on serial console in hexadecimal notation,
+// padding with leading zero if necisary to provide evenly tabulated display data.
+void PrintHex(unsigned char data);
+
+// Extract Name from DNS data. Will follow pointers used by Message Compression.
+// TODO Check for exceeding packet size.
+int nameFromDnsPointer(char* p_name_buffer, int name_buffer_pos, const int name_buffer_len, 
+    const byte* p_packet_buffer, int packet_buffer_pos);
+int nameFromDnsPointer(char* p_name_buffer, int name_buffer_pos, const int name_buffer_len,
+    const byte* p_packet_buffer, int packet_buffer_pos, const bool recurse);
+
+bool writeToBuffer(const byte value, char* p_name_buffer, int* p_name_buffer_pos, const int name_buffer_len);
+
+int parseText(char* data_buffer, const int data_buffer_len, int const data_len,
+    const byte* p_packet_buffer, int packet_buffer_pos);
+
+} // namespace mdns
+
+#endif  // MDNS_H