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listener.h
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listener.h
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/**
* Listener.h
*
* Class that listens for incoming connections
*
* @author Emiel Bruijntjes <[email protected]>
* @author David van Erkelens <[email protected]>
*
* @copyright 2016 Copernica BV
*/
/**
* Include guard
*/
#pragma once
/**
* Dependencies
*/
#include <copernica/dns.h>
/**
* Class definition
*/
class Listener : public Feedback, private TcpHandler
{
private:
/**
* The socket file descriptor
* @var int
*/
int _fd;
/**
* All file descriptors
* @var Descriptors
*/
Descriptors _descriptors;
/**
* The name
* @var std::string
*
* @todo remove this
*/
mutable std::string _name;
/**
* The IP address we're listening on
* @var Copernica::Dns::IpAddress
*/
mutable Copernica::Dns::IpAddress _ip;
/**
* The port we're listening on
* @var int
*/
mutable int _port = 0;
/**
* The file descriptors that are monitored by this handler
* @return Descriptors
*/
virtual const Descriptors &descriptors() const override
{
// expose the member
return _descriptors;
}
/**
* Method that is called when a filedescriptor becomes active
* @param fd the filedescriptor that is active
* @param flags type of activity (readable or writalble)
*/
virtual void process(int fd, int flags) override
{
// ignore if this is not even our socket
if (fd != _fd) return;
// store data about the connecting client
struct sockaddr_in client_address;
// store the struct length
unsigned int addr_length = sizeof(client_address);
// create a new socket
int newsocket = accept(_fd, (struct sockaddr *)&client_address, &addr_length);
// was socket creation succesful?
if (newsocket < 0) return;
// the result buffer
std::string buffer;
// we are going to read all the way to end of file
while (true)
{
// construct a temporary buffer
char tempbuf[4096];
// read data into the buffer
auto bytes = read(newsocket, tempbuf, 4096);
// are we done?
if (bytes <= 0) break;
// append to the full buffer
buffer.append(tempbuf, bytes);
}
// new socket can be closed again
close(newsocket);
// notify our owner
_owner->onReceived(this, buffer.data(), buffer.size());
// we're ready!
_ready = true;
}
public:
/**
* Constructor
* @param owner
*/
Listener(Feedback::Owner *owner) :
Feedback(owner),
_fd(socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0))
{
// was the socket created?
if (_fd < 0) throw std::runtime_error("failed to open socket");
// set address settings
struct sockaddr_in address;
address.sin_family = AF_INET;
address.sin_addr.s_addr = INADDR_ANY;
// bind the socket to the file descriptor
if (bind(_fd, (struct sockaddr *)&address, sizeof(address)) < 0)
{
// something went wrong...
throw std::runtime_error("failed to bind socket");
}
// listen to the socket
listen(_fd, 5);
// add the file descriptors
_descriptors.add(_fd, AMQP::readable);
}
/**
* Destructor
*/
virtual ~Listener()
{
// close the socket
close(_fd);
}
/**
* Start consuming data from the temporary queue
*/
virtual void wait() override
{
// if the object is ready yet, we do not have to wait
if (_ready) return;
// because the socket is not marked as blocking, we can just pretend
// that it is readable -- this will block until the answer comes in
process(_fd, AMQP::readable);
}
/**
* The tcp channel that is handling incoming results
* @return TcpHandler
*/
virtual TcpHandler *handler() override
{
// we are our own handler
return this;
}
/**
* Return the IP address we're listening on
* @return Copernica::Dns::IpAddress
*/
const Copernica::Dns::IpAddress &ip() const
{
// is the ip already set?
if (_ip != Copernica::Dns::IpAddress("0.0.0.0")) return _ip;
// create a socket
int s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
// was the socket creation succesful?
if (s >= 0)
{
// address of a google DNS server
Copernica::Dns::IpAddress google("8.8.8.8");
// structure to initialize
struct sockaddr_in address;
// fill the members
address.sin_family = AF_INET;
address.sin_port = htons(53);
// copy address
memcpy(&address.sin_addr, (const struct in_addr *)google, sizeof(struct in_addr));
// connect to this address
if (connect(s, (struct sockaddr *)&address, sizeof(struct sockaddr_in)) == 0)
{
// connection succeeded, find out ip
struct sockaddr_in address;
socklen_t size = sizeof(address);
// get sock name
if (getsockname(s, (struct sockaddr *)&address, &size) == 0)
{
// fetch ip address
_ip = Copernica::Dns::IpAddress(address.sin_addr);
}
}
// close socket
close(s);
}
// return
return _ip;
}
/**
* Fetch the port we're listening on
* @return int
*/
int port() const
{
// is the port already set?
if (_port > 0) return _port;
// fetch the port we're listening on
struct sockaddr_in address;
socklen_t len = sizeof(address);
getsockname(_fd, (struct sockaddr *)&address, &len);
// save port
_port = (int)ntohs(address.sin_port);
// return
return _port;
}
/**
* Name of the feedback channel
* @todo this should be changed into an "address" property
*/
virtual const std::string &name() const override
{
// did we already construct the name?
if (_name.length() > 0) return _name;
// we don't have the name yet, construct it
_name = ip().str() + ":" + std::to_string(port());
// return name
return _name;
}
};