nat_status.h

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#pragma once
 
#include "librats/util/rats_export.h"
#include "librats/core/address.h"
#include "librats/peer/peer_id.h"
 
#include <cstddef>
#include <mutex>
#include <unordered_map>
#include <vector>
 
namespace librats {
 
enum class NatMapping : uint8_t {
    Unknown,              
    Open,                 
    EndpointIndependent,  
    EndpointDependent,    
};
 
RATS_API const char* to_string(NatMapping) noexcept;
 
class ExternalAddressService {
public:
    virtual ~ExternalAddressService() = default;
 
    virtual std::vector<Address> external_udp_endpoints() const = 0;
 
    virtual NatMapping udp_mapping() const = 0;
};
 
class RATS_API NatStatus final : public ExternalAddressService {
public:
    static constexpr size_t kMaxObservers = 32;
 
    void record_udp_observation(const PeerId& reporter, const Address& external,
                                bool is_own_address);
 
    void forget(const PeerId& reporter);
 
    void reset();
 
    size_t observation_count() const;
 
    // — ExternalAddressService —
    std::vector<Address> external_udp_endpoints() const override;
    NatMapping           udp_mapping() const override;
 
private:
    struct Observation {
        Address  endpoint;
        bool     is_own_address = false;
        uint64_t seq = 0;   
    };
 
    mutable std::mutex                                       mutex_;
    std::unordered_map<PeerId, Observation, PeerId::Hash>    seen_;
    uint64_t                                                 next_seq_ = 1;
};
 
} // namespace librats