1// Copyright (c) 2024-present The Bitcoin Core developers
2// Distributed under the MIT software license, see the accompanying
3// file COPYING or https://www.opensource.org/licenses/mit-license.php.
4
5#ifndef BITCOIN_COMMON_PCP_H
6#define BITCOIN_COMMON_PCP_H
7
8#include <netaddress.h>
9#include <util/time.h>
10
11#include <array>
12#include <cstddef>
13#include <cstdint>
14#include <string>
15#include <variant>
16
17class CThreadInterrupt;
18
19// RFC6886 NAT-PMP and RFC6887 Port Control Protocol (PCP) implementation.
20// NAT-PMP and PCP use network byte order (big-endian).
21
22//! Mapping nonce size in bytes (see RFC6887 section 11.1).
23inline constexpr size_t PCP_MAP_NONCE_SIZE = 12;
24
25//! PCP mapping nonce. Arbitrary data chosen by the client to identify a mapping.
26typedef std::array<uint8_t, PCP_MAP_NONCE_SIZE> PCPMappingNonce;
27
28//! Unsuccessful response to a port mapping.
29enum class MappingError {
30    NETWORK_ERROR,  ///< Any kind of network-level error.
31    PROTOCOL_ERROR, ///< Any kind of protocol-level error, except unsupported version or no resources.
32    UNSUPP_VERSION, ///< Unsupported protocol version.
33    NO_RESOURCES,   ///< No resources available (port probably already mapped).
34};
35
36//! Successful response to a port mapping.
37struct MappingResult {
38    MappingResult(uint8_t version, const CService &internal_in, const CService &external_in, uint32_t lifetime_in):
39        version(version), internal(internal_in), external(external_in), lifetime(lifetime_in) {}
40    //! Protocol version, one of NATPMP_VERSION or PCP_VERSION.
41    uint8_t version;
42    //! Internal host:port.
43    CService internal;
44    //! External host:port.
45    CService external;
46    //! Granted lifetime of binding (seconds).
47    uint32_t lifetime;
48
49    //! Format mapping as string for logging.
50    std::string ToString() const;
51};
52
53//! Try to open a port using RFC 6886 NAT-PMP. IPv4 only.
54//!
55//! * gateway: Destination address for PCP requests (usually the default gateway).
56//! * port: Internal port, and desired external port.
57//! * lifetime: Requested lifetime in seconds for mapping. The server may assign as shorter or longer lifetime. A lifetime of 0 deletes the mapping.
58//! * num_tries: Number of tries in case of no response.
59//!
60//! Returns the external_ip:external_port of the mapping if successful, otherwise a MappingError.
61std::variant<MappingResult, MappingError> NATPMPRequestPortMap(const CNetAddr &gateway, uint16_t port, uint32_t lifetime, CThreadInterrupt& interrupt, int num_tries = 3, std::chrono::milliseconds timeout_per_try = std::chrono::milliseconds(1000));
62
63//! Try to open a port using RFC 6887 Port Control Protocol (PCP). Handles IPv4 and IPv6.
64//!
65//! * nonce: Mapping cookie. Keep this the same over renewals.
66//! * gateway: Destination address for PCP requests (usually the default gateway).
67//! * bind: Specific local bind address for IPv6 pinholing. Set this as INADDR_ANY for IPv4.
68//! * port: Internal port, and desired external port.
69//! * lifetime: Requested lifetime in seconds for mapping. The server may assign as shorter or longer lifetime. A lifetime of 0 deletes the mapping.
70//! * num_tries: Number of tries in case of no response.
71//!
72//! Returns the external_ip:external_port of the mapping if successful, otherwise a MappingError.
73std::variant<MappingResult, MappingError> PCPRequestPortMap(const PCPMappingNonce &nonce, const CNetAddr &gateway, const CNetAddr &bind, uint16_t port, uint32_t lifetime, CThreadInterrupt& interrupt, int num_tries = 3, std::chrono::milliseconds timeout_per_try = std::chrono::milliseconds(1000));
74
75#endif // BITCOIN_COMMON_PCP_H
76