lokinet/llarp/quic/address.hpp

#pragma once

#include <array>
#include <cassert>
#include <cstring>
#include <string>
#include <iosfwd>

#include <ngtcp2/ngtcp2.h>

extern "C"
{
#include <netinet/in.h>
#include <sys/socket.h>
}

// FIXME: replace use of this with a llarp::SockAddr

namespace llarp::quic
{
  union sockaddr_any
  {
    sockaddr_storage storage;
    sockaddr sa;
    sockaddr_in6 in6;
    sockaddr_in in;
  };

  class Address
  {
    sockaddr_any s{};
    ngtcp2_addr a{0, &s.sa, nullptr};

   public:
    Address() = default;
    Address(std::array<uint8_t, 4> ip, uint16_t port);
    Address(const sockaddr_any* addr, size_t addrlen);
    Address(const Address& addr)
    {
      *this = addr;
    }
    Address&
    operator=(const Address& addr);

    // Implicit conversion to sockaddr* and ngtcp2_addr& so that an Address can be passed wherever
    // one of those is expected.
    operator sockaddr*()
    {
      return a.addr;
    }
    operator const sockaddr*() const
    {
      return a.addr;
    }
    constexpr socklen_t
    sockaddr_size() const
    {
      return a.addrlen;
    }
    operator ngtcp2_addr&()
    {
      return a;
    }
    operator const ngtcp2_addr&() const
    {
      return a;
    }

    std::string
    to_string() const;
  };

  // Wraps an ngtcp2_path (which is basically just and address pair) with remote/local components.
  // Implicitly convertable to a ngtcp2_path* so that this can be passed wherever a ngtcp2_path* is
  // taken in the ngtcp2 API.
  struct Path
  {
   private:
    Address local_{}, remote_{};

   public:
    ngtcp2_path path{
        {local_.sockaddr_size(), local_, nullptr}, {remote_.sockaddr_size(), remote_, nullptr}};

    // Public accessors are const:
    const Address& local = local_;
    const Address& remote = remote_;

    Path() = default;
    Path(const Address& local, const Address& remote) : local_{local}, remote_{remote}
    {}
    Path(const Address& local, const sockaddr_any* remote_addr, size_t remote_len)
        : local_{local}, remote_{remote_addr, remote_len}
    {}
    Path(const Path& p) : local_{p.local_}, remote_{p.remote_}
    {}

    Path&
    operator=(const Path& p)
    {
      local_ = p.local_;
      remote_ = p.remote_;
      return *this;
    }

    // Equivalent to `&obj.path`, but slightly more convenient for passing into ngtcp2 functions
    // taking a ngtcp2_path pointer.
    operator ngtcp2_path*()
    {
      return &path;
    }
    operator const ngtcp2_path*() const
    {
      return &path;
    }

    std::string
    to_string() const;
  };

  std::ostream&
  operator<<(std::ostream& o, const Address& a);
  std::ostream&
  operator<<(std::ostream& o, const Path& p);

}  // namespace llarp::quic