Initial commit

src/core/user/UserToken.cc

@@ -0,0 +1,100 @@
+#include "UserToken.h"
+
+#include <folly/Random.h>
+#include <folly/base64.h>
+#include <folly/hash/Checksum.h>
+#include <folly/lang/Bits.h>
+
+#include "fdb/FDBTransaction.h"
+
+namespace hf3fs::core {
+namespace {
+const uint16_t magicNum = 0xF1DB;
+// clang-format off
+constexpr std::array<uint8_t, 18> mapping = {
+  12, 6, 0,
+  13, 7, 1,
+  14, 8, 2,
+  15, 9, 3,
+  16, 10, 4,
+  17, 11, 5,
+};
+// clang-format on
+}  // namespace
+
+String encodeUserToken(uint32_t uid, uint64_t randomv) {
+  static_assert(folly::Endian::order == folly::Endian::Order::LITTLE);
+
+  std::array<uint8_t, 18> tmp;
+  auto *p = tmp.data();
+
+  static_assert(sizeof(magicNum) == 2);
+  std::memcpy(p, &magicNum, sizeof(magicNum));
+  p += sizeof(magicNum);
+
+  static_assert(sizeof(uid) == 4);
+  std::memcpy(p, &uid, sizeof(uid));
+  p += sizeof(uid);
+
+  static_assert(sizeof(randomv) == 8);
+  std::memcpy(p, &randomv, sizeof(randomv));
+  p += sizeof(randomv);
+
+  auto crc = folly::crc32(tmp.data(), 14, 0);
+  static_assert(sizeof(crc) == 4);
+  std::memcpy(p, &crc, sizeof(crc));
+
+  std::array<char, 18> buffer;
+  for (size_t i = 0; i < 18; ++i) {
+    buffer[mapping[i]] = tmp[i];
+  }
+  return folly::base64Encode(std::string_view(buffer.data(), buffer.size()));
+}
+
+Result<std::pair<uint32_t, uint64_t>> decodeUserToken(std::string_view token) {
+  try {
+    auto decoded = folly::base64Decode(token);
+    if (decoded.size() != 18) return makeError(StatusCode::kInvalidFormat, "Decode token fail: invalid format");
+
+    std::array<uint8_t, 18> tmp;
+    for (size_t i = 0; i < 18; ++i) {
+      tmp[i] = decoded[mapping[i]];
+    }
+
+    uint16_t mn = 0;
+    uint32_t uid = 0, crc = 0;
+    uint64_t timestamp = 0;
+    auto *p = tmp.data();
+    std::memcpy(&mn, p, sizeof(mn));
+    p += sizeof(mn);
+    std::memcpy(&uid, p, sizeof(uid));
+    p += sizeof(uid);
+    std::memcpy(&timestamp, p, sizeof(timestamp));
+    p += sizeof(timestamp);
+    std::memcpy(&crc, p, sizeof(crc));
+
+    if (mn != magicNum) {
+      return makeError(StatusCode::kInvalidFormat, "Decode token fail: invalid format");
+    }
+
+    auto expectedCrc = folly::crc32(tmp.data(), 14, 0);
+    if (crc != expectedCrc) {
+      return makeError(StatusCode::kInvalidFormat, "Decode token fail: invalid crc");
+    }
+    return std::make_pair(uid, timestamp);
+  } catch (const folly::base64_decode_error &e) {
+    return makeError(StatusCode::kInvalidFormat, "Decode token fail: {}", e.what());
+  }
+}
+
+Result<flat::Uid> decodeUidFromUserToken(std::string_view token) {
+  auto r = decodeUserToken(token);
+  RETURN_ON_ERROR(r);
+  auto [uid, ts] = *r;
+  return flat::Uid{uid};
+}
+
+CoTryTask<String> encodeUserToken(uint32_t uid, kv::IReadOnlyTransaction &txn) {
+  co_return encodeUserToken(uid, folly::Random::secureRand64());
+}
+}  // namespace hf3fs::core