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/*
* Author: Sven Gothel <sgothel@jausoft.com>
* Copyright (c) 2021 Gothel Software e.K.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef SMPKEYBIN_HPP_
#define SMPKEYBIN_HPP_
#include <cstring>
#include <string>
#include <memory>
#include <cstdint>
#include <fstream>
#include <iostream>
#include "SMPTypes.hpp"
namespace direct_bt {
/**
* Storage for SMP keys including the required connection parameter.
*
* Storage for a device's BDAddressAndType, its security connection setup BTSecurityLevel + SMPIOCapability
* and optionally the initiator and responder SMPLongTermKeyInfo (LTK) and SMPSignatureResolvingKeyInfo (CSRK) within one file.
* <p>
* Since the SMPLongTermKeyInfo (LTK) and SMPSignatureResolvingKeyInfo (CSRK)
* can be optionally set due to their availability per initiator and responder,
* implementation supports mixed mode for certain devices.
* E.g. LTK responder key only etc.
* </p>
*/
class SMPKeyBin {
public:
constexpr static const uint16_t VERSION = (uint16_t)0b0101010101010101 + (uint16_t)1; // bitpattern + version
private:
uint16_t version; // 2
uint16_t size; // 2
BDAddressAndType addrAndType; // 7
BTSecurityLevel sec_level; // 1
SMPIOCapability io_cap; // 1
SMPKeyType keys_init; // 1
SMPKeyType keys_resp; // 1
SMPLongTermKeyInfo ltk_init; // 28 (optional)
SMPSignatureResolvingKeyInfo csrk_init; // 17 (optional)
SMPLongTermKeyInfo ltk_resp; // 28 (optional)
SMPSignatureResolvingKeyInfo csrk_resp; // 17 (optional)
// Min-Max: 15 - 105 bytes
bool verbose;
constexpr uint16_t calcSize() const {
uint16_t s = 0;
s += sizeof(version);
s += sizeof(size);
s += sizeof(addrAndType.address);
s += sizeof(addrAndType.type);
s += sizeof(sec_level);
s += sizeof(io_cap);
s += sizeof(keys_init);
s += sizeof(keys_resp);
if( hasLTKInit() ) {
s += sizeof(ltk_init);
}
if( hasCSRKInit() ) {
s += sizeof(csrk_init);
}
if( hasLTKResp() ) {
s += sizeof(ltk_resp);
}
if( hasCSRKResp() ) {
s += sizeof(csrk_resp);
}
return s;
}
public:
SMPKeyBin(const BDAddressAndType& addrAndType_,
const BTSecurityLevel sec_level_, const SMPIOCapability io_cap_)
: version(VERSION), size(0),
addrAndType(addrAndType_), sec_level(sec_level_), io_cap(io_cap_),
keys_init(SMPKeyType::NONE), keys_resp(SMPKeyType::NONE),
ltk_init(), csrk_init(), ltk_resp(), csrk_resp(),
verbose(false)
{ size = calcSize(); }
SMPKeyBin()
: version(VERSION), size(0),
addrAndType(), sec_level(BTSecurityLevel::UNSET), io_cap(SMPIOCapability::UNSET),
keys_init(SMPKeyType::NONE), keys_resp(SMPKeyType::NONE),
ltk_init(), csrk_init(), ltk_resp(), csrk_resp(),
verbose(false)
{ size = calcSize(); }
constexpr bool isVersionValid() const noexcept { return VERSION==version; }
constexpr uint16_t getVersion() const noexcept { return version;}
constexpr bool isSizeValid() const noexcept { return calcSize() == size;}
constexpr uint16_t getSize() const noexcept { return size;}
constexpr const BDAddressAndType& getAddrAndType() const noexcept { return addrAndType; }
constexpr BTSecurityLevel getSecLevel() const noexcept { return sec_level; }
constexpr SMPIOCapability getIOCap() const noexcept { return io_cap; }
constexpr bool hasLTKInit() const noexcept { return ( SMPKeyType::ENC_KEY & keys_init ) != SMPKeyType::NONE; }
constexpr bool hasCSRKInit() const noexcept { return ( SMPKeyType::SIGN_KEY & keys_init ) != SMPKeyType::NONE; }
constexpr const SMPLongTermKeyInfo& getLTKInit() const noexcept { return ltk_init; }
constexpr const SMPSignatureResolvingKeyInfo& getCSRKInit() const noexcept { return csrk_init; }
void setLTKInit(const SMPLongTermKeyInfo& v) noexcept {
ltk_init = v;
keys_init |= SMPKeyType::ENC_KEY;
size = calcSize();
}
void setCSRKInit(const SMPSignatureResolvingKeyInfo& v) noexcept {
csrk_init = v;
keys_init |= SMPKeyType::SIGN_KEY;
size = calcSize();
}
constexpr bool hasLTKResp() const noexcept { return ( SMPKeyType::ENC_KEY & keys_resp ) != SMPKeyType::NONE; }
constexpr bool hasCSRKResp() const noexcept { return ( SMPKeyType::SIGN_KEY & keys_resp ) != SMPKeyType::NONE; }
constexpr const SMPLongTermKeyInfo& getLTKResp() const noexcept { return ltk_resp; }
constexpr const SMPSignatureResolvingKeyInfo& getCSRKResp() const noexcept { return csrk_resp; }
void setLTKResp(const SMPLongTermKeyInfo& v) noexcept {
ltk_resp = v;
keys_resp |= SMPKeyType::ENC_KEY;
size = calcSize();
}
void setCSRKResp(const SMPSignatureResolvingKeyInfo& v) noexcept {
csrk_resp = v;
keys_resp |= SMPKeyType::SIGN_KEY;
size = calcSize();
}
void setVerbose(bool v) noexcept { verbose = v; }
constexpr bool isValid() const noexcept {
return isVersionValid() && isSizeValid() &&
BTSecurityLevel::UNSET != sec_level &&
SMPIOCapability::UNSET != io_cap &&
( !hasLTKInit() || ltk_init.isValid() ) &&
( !hasLTKResp() || ltk_resp.isValid() );
}
std::string toString() const noexcept;
constexpr_cxx20 std::string getFileBasename() const noexcept {
return "bd_"+addrAndType.address.toString()+":"+std::to_string(number(addrAndType.type))+".smpkey.bin";
}
static std::string getFileBasename(const BDAddressAndType& addrAndType_) {
return "bd_"+addrAndType_.address.toString()+":"+std::to_string(number(addrAndType_.type))+".smpkey.bin";
}
bool write(const std::string path, const std::string basename) const noexcept;
bool write(const std::string path) const noexcept {
return write( path, getFileBasename() );
}
bool read(const std::string path, const std::string basename);
bool read(const std::string path, const BDAddressAndType& addrAndType_) {
return read(path, getFileBasename(addrAndType_));
}
};
} // namespace direct_bt
#endif /* SMPKEYBIN_HPP_ */
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