1 files changed, 125 insertions, 0 deletions
diff --git a/src/librbd/crypto/CryptoInterface.h b/src/librbd/crypto/CryptoInterface.h
new file mode 100644
index 000000000..1145494a9
--- /dev/null
+++ b/src/librbd/crypto/CryptoInterface.h
@@ -0,0 +1,125 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef CEPH_LIBRBD_CRYPTO_CRYPTO_INTERFACE_H
+#define CEPH_LIBRBD_CRYPTO_CRYPTO_INTERFACE_H
+
+#include "include/buffer.h"
+#include "include/intarith.h"
+#include "librbd/io/Types.h"
+
+namespace librbd {
+namespace crypto {
+
+class CryptoInterface {
+
+public:
+  virtual ~CryptoInterface() = default;
+
+  virtual int encrypt(ceph::bufferlist* data, uint64_t image_offset) = 0;
+  virtual int decrypt(ceph::bufferlist* data, uint64_t image_offset) = 0;
+  virtual uint64_t get_block_size() const = 0;
+  virtual uint64_t get_data_offset() const = 0;
+  virtual const unsigned char* get_key() const = 0;
+  virtual int get_key_length() const = 0;
+
+  inline std::pair<uint64_t, uint64_t> get_pre_and_post_align(
+          uint64_t off, uint64_t len) {
+    if (len == 0) {
+      return std::make_pair(0, 0);
+    }
+    auto block_size = get_block_size();
+    return std::make_pair(p2phase(off, block_size),
+                          p2nphase(off + len, block_size));
+  }
+
+  inline std::pair<uint64_t, uint64_t> align(uint64_t off, uint64_t len) {
+    auto aligns = get_pre_and_post_align(off, len);
+    return std::make_pair(off - aligns.first,
+                          len + aligns.first + aligns.second);
+  }
+
+  inline bool is_aligned(uint64_t off, uint64_t len) {
+    auto aligns = get_pre_and_post_align(off, len);
+    return aligns.first == 0 && aligns.second == 0;
+  }
+
+  inline bool is_aligned(const io::ReadExtents& extents) {
+    for (const auto& extent: extents) {
+      if (!is_aligned(extent.offset, extent.length)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  inline void align_extents(const io::ReadExtents& extents,
+                            io::ReadExtents* aligned_extents) {
+    for (const auto& extent: extents) {
+      auto aligned = align(extent.offset, extent.length);
+      aligned_extents->emplace_back(aligned.first, aligned.second);
+    }
+  }
+
+  inline int decrypt_aligned_extent(io::ReadExtent& extent,
+                                    uint64_t image_offset) {
+    if (extent.length == 0 || extent.bl.length() == 0) {
+      return 0;
+    }
+
+    if (extent.extent_map.empty()) {
+      extent.extent_map.emplace_back(extent.offset, extent.bl.length());
+    }
+
+    ceph::bufferlist result_bl;
+    io::Extents result_extent_map;
+
+    ceph::bufferlist curr_block_bl;
+    auto curr_offset = extent.offset;
+    auto curr_block_start_offset = curr_offset;
+    auto curr_block_end_offset = curr_offset;
+
+    // this will add a final loop iteration for decrypting the last extent
+    extent.extent_map.emplace_back(
+            extent.offset + extent.length + get_block_size(), 0);
+
+    for (auto [off, len]: extent.extent_map) {
+      auto [aligned_off, aligned_len] = align(off, len);
+      if (aligned_off > curr_block_end_offset) {
+        curr_block_bl.append_zero(curr_block_end_offset - curr_offset);
+        auto curr_block_length = curr_block_bl.length();
+        if (curr_block_length > 0) {
+          auto r = decrypt(
+                  &curr_block_bl,
+                  image_offset + curr_block_start_offset - extent.offset);
+          if (r != 0) {
+            return r;
+          }
+
+          curr_block_bl.splice(0, curr_block_length, &result_bl);
+          result_extent_map.emplace_back(
+                  curr_block_start_offset, curr_block_length);
+        }
+
+        curr_block_start_offset = aligned_off;
+        curr_block_end_offset = aligned_off + aligned_len;
+        curr_offset = aligned_off;
+      }
+
+      curr_block_bl.append_zero(off - curr_offset);
+      extent.bl.splice(0, len, &curr_block_bl);
+      curr_offset = off + len;
+      curr_block_end_offset = aligned_off + aligned_len;
+    }
+
+    extent.bl = std::move(result_bl);
+    extent.extent_map = std::move(result_extent_map);
+
+    return 0;
+  }
+};
+
+} // namespace crypto
+} // namespace librbd
+
+#endif // CEPH_LIBRBD_CRYPTO_CRYPTO_INTERFACE_H