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nod/lib/DiscIONFS.cpp

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#include "nod/IDiscIO.hpp"
#include "nod/IFileIO.hpp"
#include "nod/Util.hpp"
#include "nod/aes.hpp"
#include <logvisor/logvisor.hpp>
namespace nod {
/*
* NFS is the image format used to distribute Wii VC games for the Wii U.
* It is an LBA format similar to WBFS but adds its own encryption layer.
* It logically stores a standard Wii disc image with partitions.
*/
class DiscIONFS : public IDiscIO {
std::vector<std::unique_ptr<IFileIO>> files;
struct NFSHead {
uint32_t magic; // EGGS
uint32_t version;
uint32_t unknown[2]; // Signature, UUID?
uint32_t lbaRangeCount;
struct {
uint32_t startBlock;
uint32_t numBlocks;
} lbaRanges[61];
uint32_t endMagic; // SGGE
} nfsHead;
uint8_t key[16];
uint32_t calculateNumFiles() const {
uint32_t totalBlockCount = 0;
for (uint32_t i = 0; i < nfsHead.lbaRangeCount; ++i)
totalBlockCount += nfsHead.lbaRanges[i].numBlocks;
return (uint64_t(totalBlockCount) * uint64_t(0x8000) + (uint64_t(0x200) + uint64_t(0xF9FFFFF))) /
uint64_t(0xFA00000);
}
struct FBO {
uint32_t file, block, lblock, offset;
};
FBO logicalToFBO(uint64_t offset) const {
auto blockAndRemBytes = nod::div(offset, uint64_t(0x8000)); /* 32768 bytes per block */
uint32_t block = UINT32_MAX;
for (uint32_t i = 0, physicalBlock = 0; i < nfsHead.lbaRangeCount; ++i) {
const auto& range = nfsHead.lbaRanges[i];
if (blockAndRemBytes.quot >= range.startBlock && blockAndRemBytes.quot - range.startBlock < range.numBlocks) {
block = physicalBlock + (blockAndRemBytes.quot - range.startBlock);
break;
}
physicalBlock += range.numBlocks;
}
/* This offset has no physical mapping, read zeroes */
if (block == UINT32_MAX)
return {UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX};
auto fileAndRemBlocks = nod::div(block, uint32_t(8000)); /* 8000 blocks per file */
return {uint32_t(fileAndRemBlocks.quot), uint32_t(fileAndRemBlocks.rem), uint32_t(blockAndRemBytes.quot),
uint32_t(blockAndRemBytes.rem)};
}
public:
DiscIONFS(std::string_view fpin, bool& err) {
/* Validate file path format */
using SignedSize = std::make_signed<std::string::size_type>::type;
const auto dotPos = SignedSize(fpin.rfind('.'));
const auto slashPos = SignedSize(fpin.find_last_of("/\\"));
if (fpin.size() <= 4 || dotPos == -1 || dotPos <= slashPos || fpin.compare(slashPos + 1, 4, "hif_") ||
fpin.compare(dotPos, fpin.size() - dotPos, ".nfs")) {
LogModule.report(logvisor::Error,
FMT_STRING("'{}' must begin with 'hif_' and end with '.nfs' to be accepted as an NFS image"),
fpin);
err = true;
return;
}
/* Load key file */
const std::string dir(fpin.begin(), fpin.begin() + slashPos + 1);
auto keyFile = NewFileIO(dir + "../code/htk.bin")->beginReadStream();
if (!keyFile)
keyFile = NewFileIO(dir + "htk.bin")->beginReadStream();
if (!keyFile) {
LogModule.report(logvisor::Error, FMT_STRING("Unable to open '{}../code/htk.bin' or '{}htk.bin'"), dir, dir);
err = true;
return;
}
if (keyFile->read(key, 16) != 16) {
LogModule.report(logvisor::Error, FMT_STRING("Unable to read from '{}../code/htk.bin' or '{}htk.bin'"), dir, dir);
err = true;
return;
}
/* Load header from first file */
const std::string firstPath = fmt::format(FMT_STRING("{}hif_{:06}.nfs"), dir, 0);
files.push_back(NewFileIO(firstPath));
auto rs = files.back()->beginReadStream();
if (!rs) {
LogModule.report(logvisor::Error, FMT_STRING("'{}' does not exist"), firstPath);
err = true;
return;
}
if (rs->read(&nfsHead, 0x200) != 0x200) {
LogModule.report(logvisor::Error, FMT_STRING("Unable to read header from '{}'"), firstPath);
err = true;
return;
}
if (std::memcmp(&nfsHead.magic, "EGGS", 4)) {
LogModule.report(logvisor::Error, FMT_STRING("Invalid magic in '{}'"), firstPath);
err = true;
return;
}
nfsHead.lbaRangeCount = SBig(nfsHead.lbaRangeCount);
for (uint32_t i = 0; i < nfsHead.lbaRangeCount; ++i) {
auto& range = nfsHead.lbaRanges[i];
range.startBlock = SBig(range.startBlock);
range.numBlocks = SBig(range.numBlocks);
}
/* Ensure remaining files exist */
const uint32_t numFiles = calculateNumFiles();
files.reserve(numFiles);
for (uint32_t i = 1; i < numFiles; ++i) {
std::string path = fmt::format(FMT_STRING("{}hif_{:06}.nfs"), dir, i);
files.push_back(NewFileIO(path));
if (!files.back()->exists()) {
LogModule.report(logvisor::Error, FMT_STRING("'{}' does not exist"), path);
err = true;
return;
}
}
}
class ReadStream : public IReadStream {
friend class DiscIONFS;
const DiscIONFS& m_parent;
std::unique_ptr<IReadStream> m_rs;
std::unique_ptr<IAES> m_aes;
/* Physical address - all UINT32_MAX indicates logical zero block */
DiscIONFS::FBO m_physAddr;
/* Logical address */
uint64_t m_offset;
/* Active file stream and its offset as set in the system.
* Block is typically one ahead of the presently decrypted block. */
uint32_t m_curFile = UINT32_MAX;
uint32_t m_curBlock = UINT32_MAX;
ReadStream(const DiscIONFS& parent, uint64_t offset, bool& err)
: m_parent(parent)
, m_aes(NewAES())
, m_physAddr({UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX})
, m_offset(offset) {
m_aes->setKey(m_parent.key);
setLogicalAddr(offset);
}
uint8_t m_encBuf[0x8000] = {};
uint8_t m_decBuf[0x8000] = {};
void setCurFile(uint32_t curFile) {
if (curFile >= m_parent.files.size()) {
LogModule.report(logvisor::Error, FMT_STRING("Out of bounds NFS file access"));
return;
}
m_curFile = curFile;
m_curBlock = UINT32_MAX;
m_rs = m_parent.files[m_curFile]->beginReadStream();
}
void setCurBlock(uint32_t curBlock) {
m_curBlock = curBlock;
m_rs->seek(m_curBlock * 0x8000 + 0x200);
}
void setPhysicalAddr(DiscIONFS::FBO physAddr) {
/* If we're just changing the offset, nothing else needs to be done */
if (m_physAddr.file == physAddr.file && m_physAddr.block == physAddr.block) {
m_physAddr.offset = physAddr.offset;
return;
}
m_physAddr = physAddr;
/* Set logical zero block */
if (m_physAddr.file == UINT32_MAX) {
memset(m_decBuf, 0, 0x8000);
return;
}
/* Make necessary file and block current with system */
if (m_physAddr.file != m_curFile)
setCurFile(m_physAddr.file);
if (m_physAddr.block != m_curBlock)
setCurBlock(m_physAddr.block);
/* Read block, handling 0x200 overlap case */
if (m_physAddr.block == 7999) {
m_rs->read(m_encBuf, 0x7E00);
setCurFile(m_curFile + 1);
m_rs->read(m_encBuf + 0x7E00, 0x200);
m_curBlock = 0;
} else {
m_rs->read(m_encBuf, 0x8000);
++m_curBlock;
}
/* Decrypt */
const uint32_t ivBuf[] = {0, 0, 0, SBig(m_physAddr.lblock)};
m_aes->decrypt((const uint8_t*)ivBuf, m_encBuf, m_decBuf, 0x8000);
}
void setLogicalAddr(uint64_t addr) { setPhysicalAddr(m_parent.logicalToFBO(m_offset)); }
public:
uint64_t read(void* buf, uint64_t length) override {
uint64_t rem = length;
uint8_t* dst = (uint8_t*)buf;
/* Perform reads on block boundaries */
while (rem) {
uint64_t readSize = rem;
uint32_t blockOffset = (m_physAddr.offset == UINT32_MAX) ? 0 : m_physAddr.offset;
if (readSize + blockOffset > 0x8000)
readSize = 0x8000 - blockOffset;
memmove(dst, m_decBuf + blockOffset, readSize);
dst += readSize;
rem -= readSize;
m_offset += readSize;
setLogicalAddr(m_offset);
}
return dst - (uint8_t*)buf;
}
uint64_t position() const override { return m_offset; }
void seek(int64_t offset, int whence) override {
if (whence == SEEK_SET)
m_offset = offset;
else if (whence == SEEK_CUR)
m_offset += offset;
else
return;
setLogicalAddr(m_offset);
}
};
std::unique_ptr<IReadStream> beginReadStream(uint64_t offset) const override {
bool err = false;
auto ret = std::unique_ptr<IReadStream>(new ReadStream(*this, offset, err));
if (err)
return {};
return ret;
}
std::unique_ptr<IWriteStream> beginWriteStream(uint64_t offset) const override { return {}; }
bool hasWiiCrypto() const override { return false; }
};
std::unique_ptr<IDiscIO> NewDiscIONFS(std::string_view path) {
bool err = false;
auto ret = std::make_unique<DiscIONFS>(path, err);
if (err)
return {};
return ret;
}
} // namespace nod
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