c++ boost raw socket setup - c++

Question

I'm doing some small project, trying to setup RAW socket, proof of concept program just to get socket up and running:
io.hpp:
#pragma once
#include <cstdlib>
#include <iostream>
#include <boost/asio.hpp>
#include <net/ethernet.h>
#include <sys/socket.h>
#include <linux/if_packet.h>
// change max length to bytes received
template <typename Protocol>
class ll_endpoint
{
private:
sockaddr_ll sockaddr;
public:
typedef Protocol protocol_type;
typedef boost::asio::detail::socket_addr_type data_type;
ll_endpoint(char* ifname)
{
sockaddr.sll_family = PF_PACKET;
sockaddr.sll_protocol = htons(ETH_P_ALL);
sockaddr.sll_ifindex = if_nametoindex(ifname);
sockaddr.sll_hatype = 1;
}
ll_endpoint& operator=(const ll_endpoint& other)
{
sockaddr = other.sockaddr;
return *this;
}
protocol_type protocol() const
{
return protocol_type();
}
data_type* data()
{
return (struct sockaddr*)&sockaddr;
}
const data_type* data() const
{
return (struct sockaddr*)&sockaddr;
}
std::size_t size() const
{
return sizeof(sockaddr);
}
void resize(std::size_t size)
{
/* nothing we can do here */
}
std::size_t capacity() const
{
return sizeof(sockaddr);
}
friend bool operator==(const ll_endpoint<Protocol>& e1,
const ll_endpoint<Protocol>& e2)
{
return ( e1.sockaddr.sll_addr == e2.sockaddr.sll_addr );
}
friend bool operator!=(const ll_endpoint<Protocol>& e1,
const ll_endpoint<Protocol>& e2)
{
return !(e1.sockaddr.sll_addr == e2.sockaddr.sll_addr);
}
friend bool operator<(const ll_endpoint<Protocol>& e1,
const ll_endpoint<Protocol>& e2)
{
return e1.sockaddr.sll_addr < e2.sockaddr.sll_addr;
}
friend bool operator>(const ll_endpoint<Protocol>& e1,
const ll_endpoint<Protocol>& e2)
{
return e2.sockaddr.sll_addr < e1.sockaddr.sll_addr;
}
friend bool operator<=(const ll_endpoint<Protocol>& e1,
const ll_endpoint<Protocol>& e2)
{
return !(e2 < e1);
}
friend bool operator>=(const ll_endpoint<Protocol>& e1,
const ll_endpoint<Protocol>& e2)
{
return !(e1 < e2);
}
};
class ll_protocol
{
public:
typedef boost::asio::basic_raw_socket<ll_protocol> socket;
typedef ll_endpoint<ll_protocol> endpoint;
int type() const {
return SOCK_RAW;
}
int protocol() const {
return protocol_;
}
int family() const{
return family_;
}
ll_protocol(int protocol, int family): protocol_(protocol), family_(family) {}
ll_protocol(): protocol_(htons(ETH_P_ALL)), family_(PF_PACKET) {}
private:
int protocol_;
int family_;
};
class IO {
typedef boost::asio::basic_raw_socket<ll_protocol> socket;
typedef ll_endpoint<ll_protocol> endpoint;
public:
IO(boost::asio::io_context& io_context, char* ifname)
: socket_(io_context, ll_endpoint<ll_protocol>(ifname))
{
do_receive();
}
void do_receive()
{
socket_.async_receive_from(
boost::asio::buffer(data_, max_length), sender_endpoint_,
[this](boost::system::error_code ec, std::size_t bytes_recvd) // <--- handler
{
if (!ec && bytes_recvd > 0)
{
do_send(bytes_recvd);
}
else
{
do_receive();
}
});
}
void do_send(std::size_t length)
{
socket_.async_send_to(
boost::asio::buffer(data_, length), sender_endpoint_,
[this](boost::system::error_code /*ec*/, std::size_t /*bytes_sent*/)
{
do_receive();
});
}
private:
socket socket_;
endpoint sender_endpoint_;
enum { max_length = 9000 };
char data_[max_length]; // change to vector?, const std::vector<uint8_t>& packet
};
Main.cpp
#include <cctype>
#include <cstdlib>
#include <iostream>
#include <boost/asio.hpp>
#include "io.hpp"
int main(int argc, char *argv[]) {
try
{
boost::asio::io_context io_context;
IO s(io_context, argv[1]);
io_context.run();
}
catch (std::exception& e)
{
std::cerr << "Exception: " << e.what() << "\n";
}
return 0;
}
On compile I get this error:
io.hpp:142:56: error: expected primary-expression before ‘>’ token
142 | : socket_(io_context, sender_endpoint_<ll_protocol>(ifname))
| ^
io.hpp:142:65: error: no matching function for call to ‘ll_endpoint<ll_protocol>::ll_endpoint()’
142 | : socket_(io_context, sender_endpoint_<ll_protocol>(ifname))
| ^
io.hpp:25:5: note: candidate: ‘ll_endpoint<Protocol>::ll_endpoint(const char*) [with Protocol = ll_protocol]’
25 | ll_endpoint(const char* ifname)
| ^~~~~~~~~~~
io.hpp:25:5: note: candidate expects 1 argument, 0 provided <--- but why *thanks Useless for spotting this, however even I pass something error is the same
Is it a template misuse and what I am missing?
expectation is to setup socket in a similar way to https://www.boost.org/doc/libs/1_70_0/doc/html/boost_asio/example/cpp11/echo/async_udp_echo_server.cpp

Answer 1

The member variable sender_endpoint_ have the type endpoint, which is an alias of ll_endpoint<ll_protocol>.
The type endpoint is a concrete type, it's not a template. So adding template-arguments for sender_endpoint_ makes no sense.
Just remove the template-arguments: sender_endpoint_(ifname)