1 files changed, 213 insertions, 0 deletions
diff --git a/fs/bcachefs/checksum.h b/fs/bcachefs/checksum.h
new file mode 100644
index 0000000000..13998388c5
--- /dev/null
+++ b/fs/bcachefs/checksum.h
@@ -0,0 +1,213 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_CHECKSUM_H
+#define _BCACHEFS_CHECKSUM_H
+
+#include "bcachefs.h"
+#include "extents_types.h"
+#include "super-io.h"
+
+#include <linux/crc64.h>
+#include <crypto/chacha.h>
+
+static inline bool bch2_checksum_mergeable(unsigned type)
+{
+
+	switch (type) {
+	case BCH_CSUM_none:
+	case BCH_CSUM_crc32c:
+	case BCH_CSUM_crc64:
+		return true;
+	default:
+		return false;
+	}
+}
+
+struct bch_csum bch2_checksum_merge(unsigned, struct bch_csum,
+				    struct bch_csum, size_t);
+
+#define BCH_NONCE_EXTENT	cpu_to_le32(1 << 28)
+#define BCH_NONCE_BTREE		cpu_to_le32(2 << 28)
+#define BCH_NONCE_JOURNAL	cpu_to_le32(3 << 28)
+#define BCH_NONCE_PRIO		cpu_to_le32(4 << 28)
+#define BCH_NONCE_POLY		cpu_to_le32(1 << 31)
+
+struct bch_csum bch2_checksum(struct bch_fs *, unsigned, struct nonce,
+			     const void *, size_t);
+
+/*
+ * This is used for various on disk data structures - bch_sb, prio_set, bset,
+ * jset: The checksum is _always_ the first field of these structs
+ */
+#define csum_vstruct(_c, _type, _nonce, _i)				\
+({									\
+	const void *_start = ((const void *) (_i)) + sizeof((_i)->csum);\
+									\
+	bch2_checksum(_c, _type, _nonce, _start, vstruct_end(_i) - _start);\
+})
+
+int bch2_chacha_encrypt_key(struct bch_key *, struct nonce, void *, size_t);
+int bch2_request_key(struct bch_sb *, struct bch_key *);
+#ifndef __KERNEL__
+int bch2_revoke_key(struct bch_sb *);
+#endif
+
+int bch2_encrypt(struct bch_fs *, unsigned, struct nonce,
+		 void *data, size_t);
+
+struct bch_csum bch2_checksum_bio(struct bch_fs *, unsigned,
+				  struct nonce, struct bio *);
+
+int bch2_rechecksum_bio(struct bch_fs *, struct bio *, struct bversion,
+			struct bch_extent_crc_unpacked,
+			struct bch_extent_crc_unpacked *,
+			struct bch_extent_crc_unpacked *,
+			unsigned, unsigned, unsigned);
+
+int __bch2_encrypt_bio(struct bch_fs *, unsigned,
+		       struct nonce, struct bio *);
+
+static inline int bch2_encrypt_bio(struct bch_fs *c, unsigned type,
+				   struct nonce nonce, struct bio *bio)
+{
+	return bch2_csum_type_is_encryption(type)
+		? __bch2_encrypt_bio(c, type, nonce, bio)
+		: 0;
+}
+
+extern const struct bch_sb_field_ops bch_sb_field_ops_crypt;
+
+int bch2_decrypt_sb_key(struct bch_fs *, struct bch_sb_field_crypt *,
+			struct bch_key *);
+
+int bch2_disable_encryption(struct bch_fs *);
+int bch2_enable_encryption(struct bch_fs *, bool);
+
+void bch2_fs_encryption_exit(struct bch_fs *);
+int bch2_fs_encryption_init(struct bch_fs *);
+
+static inline enum bch_csum_type bch2_csum_opt_to_type(enum bch_csum_opts type,
+						       bool data)
+{
+	switch (type) {
+	case BCH_CSUM_OPT_none:
+		return BCH_CSUM_none;
+	case BCH_CSUM_OPT_crc32c:
+		return data ? BCH_CSUM_crc32c : BCH_CSUM_crc32c_nonzero;
+	case BCH_CSUM_OPT_crc64:
+		return data ? BCH_CSUM_crc64 : BCH_CSUM_crc64_nonzero;
+	case BCH_CSUM_OPT_xxhash:
+		return BCH_CSUM_xxhash;
+	default:
+		BUG();
+	}
+}
+
+static inline enum bch_csum_type bch2_data_checksum_type(struct bch_fs *c,
+							 struct bch_io_opts opts)
+{
+	if (opts.nocow)
+		return 0;
+
+	if (c->sb.encryption_type)
+		return c->opts.wide_macs
+			? BCH_CSUM_chacha20_poly1305_128
+			: BCH_CSUM_chacha20_poly1305_80;
+
+	return bch2_csum_opt_to_type(opts.data_checksum, true);
+}
+
+static inline enum bch_csum_type bch2_meta_checksum_type(struct bch_fs *c)
+{
+	if (c->sb.encryption_type)
+		return BCH_CSUM_chacha20_poly1305_128;
+
+	return bch2_csum_opt_to_type(c->opts.metadata_checksum, false);
+}
+
+static inline bool bch2_checksum_type_valid(const struct bch_fs *c,
+					   unsigned type)
+{
+	if (type >= BCH_CSUM_NR)
+		return false;
+
+	if (bch2_csum_type_is_encryption(type) && !c->chacha20)
+		return false;
+
+	return true;
+}
+
+/* returns true if not equal */
+static inline bool bch2_crc_cmp(struct bch_csum l, struct bch_csum r)
+{
+	/*
+	 * XXX: need some way of preventing the compiler from optimizing this
+	 * into a form that isn't constant time..
+	 */
+	return ((l.lo ^ r.lo) | (l.hi ^ r.hi)) != 0;
+}
+
+/* for skipping ahead and encrypting/decrypting at an offset: */
+static inline struct nonce nonce_add(struct nonce nonce, unsigned offset)
+{
+	EBUG_ON(offset & (CHACHA_BLOCK_SIZE - 1));
+
+	le32_add_cpu(&nonce.d[0], offset / CHACHA_BLOCK_SIZE);
+	return nonce;
+}
+
+static inline struct nonce null_nonce(void)
+{
+	struct nonce ret;
+
+	memset(&ret, 0, sizeof(ret));
+	return ret;
+}
+
+static inline struct nonce extent_nonce(struct bversion version,
+					struct bch_extent_crc_unpacked crc)
+{
+	unsigned compression_type = crc_is_compressed(crc)
+		? crc.compression_type
+		: 0;
+	unsigned size = compression_type ? crc.uncompressed_size : 0;
+	struct nonce nonce = (struct nonce) {{
+		[0] = cpu_to_le32(size << 22),
+		[1] = cpu_to_le32(version.lo),
+		[2] = cpu_to_le32(version.lo >> 32),
+		[3] = cpu_to_le32(version.hi|
+				  (compression_type << 24))^BCH_NONCE_EXTENT,
+	}};
+
+	return nonce_add(nonce, crc.nonce << 9);
+}
+
+static inline bool bch2_key_is_encrypted(struct bch_encrypted_key *key)
+{
+	return le64_to_cpu(key->magic) != BCH_KEY_MAGIC;
+}
+
+static inline struct nonce __bch2_sb_key_nonce(struct bch_sb *sb)
+{
+	__le64 magic = __bch2_sb_magic(sb);
+
+	return (struct nonce) {{
+		[0] = 0,
+		[1] = 0,
+		[2] = ((__le32 *) &magic)[0],
+		[3] = ((__le32 *) &magic)[1],
+	}};
+}
+
+static inline struct nonce bch2_sb_key_nonce(struct bch_fs *c)
+{
+	__le64 magic = bch2_sb_magic(c);
+
+	return (struct nonce) {{
+		[0] = 0,
+		[1] = 0,
+		[2] = ((__le32 *) &magic)[0],
+		[3] = ((__le32 *) &magic)[1],
+	}};
+}
+
+#endif /* _BCACHEFS_CHECKSUM_H */