A class for representing a SRV DNS resource record. More...

#include <AsyncDnsResourceRecord.h>

Inheritance diagram for Async::DnsResourceRecordSRV:

Public Types
using	Prio = unsigned int

using	Weight = unsigned int

using	Port = unsigned int

using	Target = std::string

Public Types inherited from Async::DnsResourceRecordCRTP< DnsResourceRecordSRV >
using	List
	The type for a list of resource records.

Public Types inherited from Async::DnsResourceRecord
enum class	Type { ANY , A , PTR , CNAME , SRV , A , PTR , CNAME , SRV }
	The record type. More...

enum class	Class { IN , IN }
	The record class. More...

enum class	Type { ANY , A , PTR , CNAME , SRV , A , PTR , CNAME , SRV }

enum class	Class { IN , IN }

using	Name = std::string

using	Ttl = uint32_t

using	List = std::vector<std::unique_ptr<DnsResourceRecord>>
	The type for a list of resource records.

Public Member Functions
	DnsResourceRecordSRV (const Name &name, Ttl ttl, Prio prio, Weight weight, Port port, const Target &target)
	Constructor.

virtual bool	operator== (const DnsResourceRecordSRV &other) const
	Equality comparison operator.

virtual std::string	toString (void) const
	The string representation of this record.

void	setPrio (Prio prio)
	Set the prio for this record.

Prio	prio (void) const
	The prio for this record.

void	setWeight (Weight weight)
	Set the weight for this record.

Weight	weight (void) const
	The weight for this record.

void	setPort (Port port)
	Set the network port for this record.

Port	port (void) const
	The network port for this record.

void	setTarget (const Target &target)
	Set the FQDN for this record.

const Target &	target (void) const
	The FQDN for this record.

	DnsResourceRecordSRV (const std::string &name, uint32_t ttl, unsigned int prio, unsigned int weight, unsigned int port, const std::string &target)

	~DnsResourceRecordSRV (void)

virtual const Type	type (void) const
	The type of record.

virtual std::string	toString (void) const
	The string representation of this record.

void	setPrio (unsigned int prio)

unsigned int	prio (void) const

void	setWeight (unsigned int weight)

unsigned int	weight (void) const

void	setPort (unsigned int port)

unsigned int	port (void) const

void	setTarget (const std::string &target)

const std::string &	target (void) const

Public Member Functions inherited from Async::DnsResourceRecordCRTP< DnsResourceRecordSRV >
	DnsResourceRecordCRTP (const Name &name, Ttl ttl)
	Constructor.

virtual DnsResourceRecord *	clone (void) const
	Clone this class.

virtual bool	operator== (const DnsResourceRecord &other) const
	Equality comparison operator.

Public Member Functions inherited from Async::DnsResourceRecord
	DnsResourceRecord (const Name &name, Ttl ttl)
	Constructor.

virtual	~DnsResourceRecord (void)
	Destructor.

Class	classId (void) const
	The DNS class for the record.

const char *	classStr (void) const
	The DNS class for the record as a string.

const std::string &	typeStr (void) const
	The type of record as a string.

void	setName (const Name &name)
	Set the name for this record.

const Name &	name (void) const
	The name of this record.

void	setTtl (Ttl ttl)
	Set the TTL for this record.

Ttl	ttl (void) const
	The TTL for this record.

	DnsResourceRecord (const std::string &name, uint32_t ttl)
	Default constructor.

	DnsResourceRecord (const DnsResourceRecord &)=delete
	Disallow copy construction.

DnsResourceRecord &	operator= (const DnsResourceRecord &)=delete
	Disallow copy assignment.

virtual	~DnsResourceRecord (void)
	Destructor.

Class	classId (void) const
	A_brief_member_function_description.

const char *	classStr (void) const

const std::string &	typeStr (void) const

void	setName (const std::string &name)

const std::string &	name (void) const

void	setTtl (uint32_t ttl)

uint32_t	ttl (void) const

Static Public Member Functions
static const Type	staticType (void)
	The type for this specific class.

static const Type	staticType (void)

Static Public Member Functions inherited from Async::DnsResourceRecord
static const Type	staticType (void)
	The type for this specific class.

static const std::string &	typeToString (Type type)
	The type for this specific class represented as a string.

static const std::string &	typeToString (Type type)

Additional Inherited Members
Static Public Attributes inherited from Async::DnsResourceRecord
static constexpr Ttl	MAX_TTL = 0x7fffffff
	The maximum allowed value for a TTL.

Detailed Description

A class for representing a SRV DNS resource record.

Author: Tobias Blomberg / SM0SVX

Date: 2021-05-22

This class represents an SRV DNS resource record. One or more resource records is the result of performing a DNS query. This specific resource record maps a service name to information for that service.

This is one of the more advanced resource record types. A query for this type of resource record often return multiple entries. Each entry contain information about priority, weight, port and target.

Priority: The priority of the target host, lower value means more preferred. Weight: A relative weight for records with the same priority, higher value means higher chance of getting picked. Port: the TCP or UDP port on which the service is to be found. Target: the canonical hostname of the machine providing the service, ending in a dot.

An example of SRV records in textual form that might be found in a zone file might be the following:

_sip._tcp.example.com. 86400 IN SRV 0 60 5060 sipserver1.example.com. _sip._tcp.example.com. 86400 IN SRV 0 40 5060 sipserver2.example.com. _sip._tcp.example.com. 86400 IN SRV 1 100 5061 sipserver-backup.example.com.

The client should choose sipserver1 or sipserver2 first. Sipserver1 should be chosen 60% of the time and sipserver2 should be chosen 40% of the time. If none of the two first servers are reachable the client should try to connect to sipserver-backup.

#include <iostream>
#include <AsyncCppApplication.h>
#include <AsyncDnsLookup.h>
 
using namespace Async;
 
class MyClass : public sigc::trackable
{
  public:
    MyClass(void)
    {
      dns.resultsReady.connect(mem_fun(*this, &MyClass::onResultsReady));
 
      dns.lookup("www.svxlink.org");
      //dns.lookup("www.svxlink.org", DnsLookup::Type::CNAME);
      //dns.lookup("185.199.110.153");
      //dns.lookup("185.199.110.153", DnsLookup::Type::PTR);
      //dns.lookup("153.110.199.185.in-addr.arpa.", DnsLookup::Type::PTR);
 
      //std::string srv = "_svxreflector._tcp.test.svxlink.org";
      //dns.addStaticResourceRecord(
      //    new DnsResourceRecordSRV(srv, 3600, 15, 10, 5304, "localhost."));
      //dns.lookup(srv, DnsLookup::Type::SRV);
 
      std::cout << "Starting " << dns.typeStr() << " record query for \""
                << dns.label() << "\"..." << std::endl;
    }
 
    void onResultsReady(DnsLookup& dns)
    {
      if (!dns.lookupFailed())
      {
          // Simple IP address lookup API
        std::cout << "IP addresses received:\n";
        for (auto& addr : dns.addresses())
        {
          std::cout << addr << std::endl;
        }
        std::cout << std::endl;
 
          // Access to all resource records
        std::cout << "All resource records received:\n";
        for (auto& rr : dns.resourceRecords())
        {
          std::cout << rr->toString() << std::endl;
        }
        std::cout << std::endl;
 
          // Access A records with full detail
        DnsResourceRecordA::List a_rrs;
        dns.resourceRecords(a_rrs);
        if (!a_rrs.empty())
        {
          std::cout << "A records received:\n";
          for (auto& rr : a_rrs)
          {
            std::cout << rr->name() << "\t" << rr->ttl() << "\t" << rr->ip()
                      << std::endl;
          }
          std::cout << std::endl;
        }
 
          // Access PTR records with full detail
        DnsResourceRecordPTR::List ptr_rrs;
        dns.resourceRecords(ptr_rrs);
        if (!ptr_rrs.empty())
        {
          std::cout << "PTR records received:\n";
          for (auto& rr : ptr_rrs)
          {
            std::cout << rr->name() << "\t" << rr->ttl() << "\t" << rr->dname()
                      << std::endl;
          }
          std::cout << std::endl;
        }
 
          // Access CNAME records with full detail
        DnsResourceRecordCNAME::List cname_rrs;
        dns.resourceRecords(cname_rrs);
        if (!cname_rrs.empty())
        {
          std::cout << "CNAME records received:\n";
          for (auto& rr : cname_rrs)
          {
            std::cout << rr->name() << "\t" << rr->ttl() << "\t" << rr->cname()
                      << std::endl;
          }
          std::cout << std::endl;
        }
 
          // Access SRV records with full detail
        DnsResourceRecordSRV::List srv_rrs;
        dns.resourceRecords(srv_rrs);
        if (!srv_rrs.empty())
        {
          std::cout << "SRV records received:\n";
          for (auto& rr : srv_rrs)
          {
            std::cout << rr->name() << "\t" << rr->ttl() << "\t" << rr->prio()
                      << " " << rr->weight() << " " << rr->port() << " "
                      << rr->target() << std::endl;
          }
        }
      }
      else
      {
        std::cout << "*** ERROR: The " << dns.typeStr()
                  << " record DNS lookup for " << dns.label()
                  << " failed" << std::endl;
      }
 
      Application::app().quit();
    }
 
  private:
    DnsLookup dns;
};
 
int main(int argc, char **argv)
{
  CppApplication app;
  MyClass dns;
  app.exec();
}

Definition at line 275 of file AsyncResourceRecord.h.

Member Typedef Documentation

◆ Port

using Async::DnsResourceRecordSRV::Port = unsigned int

Definition at line 585 of file AsyncDnsResourceRecord.h.

◆ Prio

using Async::DnsResourceRecordSRV::Prio = unsigned int

Definition at line 583 of file AsyncDnsResourceRecord.h.

◆ Target

using Async::DnsResourceRecordSRV::Target = std::string

Definition at line 586 of file AsyncDnsResourceRecord.h.

◆ Weight

using Async::DnsResourceRecordSRV::Weight = unsigned int

Definition at line 584 of file AsyncDnsResourceRecord.h.

Constructor & Destructor Documentation

◆ DnsResourceRecordSRV() [1/2]

Async::DnsResourceRecordSRV::DnsResourceRecordSRV	(	const Name &	name,
		Ttl	ttl,
		Prio	prio,
		Weight	weight,
		Port	port,
		const Target &	target )

inline

Constructor.

Parameters

name	The name of this record
ttl	The time-to-live, in seconds, for this record
prio	The priority for this record
weight	The weight for this record
port	The network port for this record
target	The FQDN associaated with this record name

Definition at line 602 of file AsyncDnsResourceRecord.h.

◆ DnsResourceRecordSRV() [2/2]

Async::DnsResourceRecordSRV::DnsResourceRecordSRV	(	const std::string &	name,
		uint32_t	ttl,
		unsigned int	prio,
		unsigned int	weight,
		unsigned int	port,
		const std::string &	target )

inline

Definition at line 280 of file AsyncResourceRecord.h.

◆ ~DnsResourceRecordSRV()

Async::DnsResourceRecordSRV::~DnsResourceRecordSRV ( void )

inline

Definition at line 285 of file AsyncResourceRecord.h.

Member Function Documentation

◆ operator==()

virtual bool Async::DnsResourceRecordSRV::operator== ( const DnsResourceRecordSRV & other ) const

inlinevirtual

Equality comparison operator.

Parameters

other The other resource record to comapare to

Returns: Return true if the two records are equal

NOTE: The TTL is not used in the comparison.

Implements Async::DnsResourceRecordCRTP< DnsResourceRecordSRV >.

Definition at line 614 of file AsyncDnsResourceRecord.h.

References Async::DnsResourceRecord::operator==(), port(), prio(), target(), and weight().

◆ port() [1/2]

Port Async::DnsResourceRecordSRV::port ( void ) const

inline

The network port for this record.

Returns: Return the network port number

Definition at line 669 of file AsyncDnsResourceRecord.h.

Referenced by operator==(), setPort(), setPort(), and toString().

◆ port() [2/2]

unsigned int Async::DnsResourceRecordSRV::port ( void ) const

inline

Definition at line 303 of file AsyncResourceRecord.h.

◆ prio() [1/2]

Prio Async::DnsResourceRecordSRV::prio ( void ) const

inline

The prio for this record.

Returns: The prio number for this record (lower mean higher prio)

Definition at line 645 of file AsyncDnsResourceRecord.h.

Referenced by operator==(), setPrio(), setPrio(), and toString().

◆ prio() [2/2]

unsigned int Async::DnsResourceRecordSRV::prio ( void ) const

inline

Definition at line 297 of file AsyncResourceRecord.h.

◆ setPort() [1/2]

void Async::DnsResourceRecordSRV::setPort ( Port port )

inline

Set the network port for this record.

Parameters

port	The new network port number

Definition at line 663 of file AsyncDnsResourceRecord.h.

References port().

◆ setPort() [2/2]

void Async::DnsResourceRecordSRV::setPort ( unsigned int port )

inline

Definition at line 302 of file AsyncResourceRecord.h.

References port().

◆ setPrio() [1/2]

void Async::DnsResourceRecordSRV::setPrio ( Prio prio )

inline

Set the prio for this record.

Parameters

prio	The new priority for this record (lower mean higher prio)

Definition at line 639 of file AsyncDnsResourceRecord.h.

References prio().

◆ setPrio() [2/2]

void Async::DnsResourceRecordSRV::setPrio ( unsigned int prio )

inline

Definition at line 296 of file AsyncResourceRecord.h.

References prio().

◆ setTarget() [1/2]

void Async::DnsResourceRecordSRV::setTarget ( const std::string & target )

inline

Definition at line 305 of file AsyncResourceRecord.h.

References target().

◆ setTarget() [2/2]

void Async::DnsResourceRecordSRV::setTarget ( const Target & target )

inline

Set the FQDN for this record.

Parameters

target The new FQDN for this record

Definition at line 675 of file AsyncDnsResourceRecord.h.

References target().

◆ setWeight() [1/2]

void Async::DnsResourceRecordSRV::setWeight ( unsigned int weight )

inline

Definition at line 299 of file AsyncResourceRecord.h.

References weight().

◆ setWeight() [2/2]

void Async::DnsResourceRecordSRV::setWeight ( Weight weight )

inline

Set the weight for this record.

Parameters

weight The new weight for this record

Definition at line 651 of file AsyncDnsResourceRecord.h.

References weight().

◆ staticType() [1/2]

static const Type Async::DnsResourceRecordSRV::staticType ( void )

inlinestatic

The type for this specific class.

Definition at line 591 of file AsyncDnsResourceRecord.h.

References Async::DnsResourceRecord::SRV.

Referenced by type().

◆ staticType() [2/2]

static const Type Async::DnsResourceRecordSRV::staticType ( void )

inlinestatic

Definition at line 278 of file AsyncResourceRecord.h.

References Async::DnsResourceRecord::SRV.

◆ target() [1/2]

const Target & Async::DnsResourceRecordSRV::target ( void ) const

inline

The FQDN for this record.

Returns: Return the FQDN for this record

Definition at line 681 of file AsyncDnsResourceRecord.h.

Referenced by operator==(), setTarget(), setTarget(), and toString().

◆ target() [2/2]

const std::string & Async::DnsResourceRecordSRV::target ( void ) const

inline

Definition at line 306 of file AsyncResourceRecord.h.

◆ toString() [1/2]

virtual std::string Async::DnsResourceRecordSRV::toString ( void ) const

inlinevirtual

The string representation of this record.

Returns: Return the string representation of this record

Reimplemented from Async::DnsResourceRecord.

Definition at line 627 of file AsyncDnsResourceRecord.h.

References port(), prio(), target(), Async::DnsResourceRecord::toString(), and weight().

◆ toString() [2/2]

virtual std::string Async::DnsResourceRecordSRV::toString ( void ) const

inlinevirtual

The string representation of this record.

Returns: Return the string representation of this record

Reimplemented from Async::DnsResourceRecord.

Definition at line 288 of file AsyncResourceRecord.h.

References port(), prio(), target(), Async::DnsResourceRecord::toString(), and weight().

◆ type()

virtual const Type Async::DnsResourceRecordSRV::type ( void ) const

inlinevirtual

The type of record.

Returns: Return the type of this record

Reimplemented from Async::DnsResourceRecordCRTP< DnsResourceRecordSRV >.

Definition at line 287 of file AsyncResourceRecord.h.

References staticType().

◆ weight() [1/2]

Weight Async::DnsResourceRecordSRV::weight ( void ) const

inline

The weight for this record.

Returns: Return the weight for this record

Definition at line 657 of file AsyncDnsResourceRecord.h.

Referenced by operator==(), setWeight(), setWeight(), and toString().

◆ weight() [2/2]

unsigned int Async::DnsResourceRecordSRV::weight ( void ) const

inline

Definition at line 300 of file AsyncResourceRecord.h.

The documentation for this class was generated from the following files:

Public Types

Public Member Functions

Static Public Member Functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ Port

◆ Prio

◆ Target

◆ Weight

Constructor & Destructor Documentation

◆ DnsResourceRecordSRV() [1/2]

◆ DnsResourceRecordSRV() [2/2]

◆ ~DnsResourceRecordSRV()

Member Function Documentation

◆ operator==()

◆ port() [1/2]

◆ port() [2/2]

◆ prio() [1/2]

◆ prio() [2/2]

◆ setPort() [1/2]

◆ setPort() [2/2]

◆ setPrio() [1/2]

◆ setPrio() [2/2]

◆ setTarget() [1/2]

◆ setTarget() [2/2]

◆ setWeight() [1/2]

◆ setWeight() [2/2]

◆ staticType() [1/2]

◆ staticType() [2/2]

◆ target() [1/2]

◆ target() [2/2]

◆ toString() [1/2]

◆ toString() [2/2]

◆ type()

◆ weight() [1/2]

◆ weight() [2/2]