Rework hash implementations to provide additional algorithms.

Provide a generic hash interface, rework SHA-1 to use the interface, and
also add code for SHA-224/SHA-256.

diff --git a/Makefile b/Makefile
index e707305..a57062c 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -5,8 +5,8 @@ CXXFLAGS=-O -Wall -Wextra -D_FILE_OFFSET_BITS=64 $(DEBUG) \
         -DCUMULUS_VERSION=$(shell cat version)
 LDFLAGS=$(DEBUG) $(shell pkg-config --libs $(PACKAGES))
 
-THIRD_PARTY_SRCS=chunk.cc sha1.cc
-SRCS=exclude.cc localdb.cc main.cc metadata.cc ref.cc remote.cc \
+THIRD_PARTY_SRCS=chunk.cc sha1.cc sha256.cc
+SRCS=exclude.cc hash.cc localdb.cc main.cc metadata.cc ref.cc remote.cc \
      store.cc subfile.cc util.cc $(addprefix third_party/,$(THIRD_PARTY_SRCS))
 OBJS=$(SRCS:.cc=.o)
 

diff --git a/hash.cc b/hash.cc
new file mode 100644 (file)
index 0000000..2054bcc
--- /dev/null
+++ b/hash.cc
@@ -0,0 +1,105 @@
+/* Cumulus: Smart Filesystem Backup to Dumb Servers
+ *
+ * Copyright (C) 2012  Michael Vrable <vrable@cs.hmc.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <map>
+#include <string>
+
+#include "hash.h"
+
+using std::map;
+using std::string;
+
+static map<string, Hash *(*)()> hash_registry;
+
+void Hash::Register(const std::string& name, Hash *(*constructor)())
+{
+    printf("Registered hash algorithm %s\n", name.c_str());
+    hash_registry.insert(make_pair(name, constructor));
+}
+
+Hash *Hash::New()
+{
+    // TODO: Make generic
+    return New("sha224");
+}
+
+Hash *Hash::New(const std::string& name)
+{
+    Hash *(*constructor)() = hash_registry[name];
+    if (!constructor)
+        return NULL;
+    else
+        return constructor();
+}
+
+bool Hash::update_from_file(const char *filename)
+{
+    FILE *f = fopen(filename, "rb");
+    if (f == NULL)
+        return false;
+
+    while (!feof(f)) {
+        char buf[4096];
+        size_t bytes = fread(buf, 1, sizeof(buf), f);
+
+        if (ferror(f)) {
+            fclose(f);
+            return false;
+        }
+
+        update(buf, bytes);
+    }
+
+    fclose(f);
+    return true;
+}
+
+const uint8_t *Hash::digest()
+{
+    if (!digest_bytes) {
+        digest_bytes = finalize();
+    }
+
+    return digest_bytes;
+}
+
+string Hash::digest_str()
+{
+    const uint8_t *raw_digest = digest();
+    size_t len = digest_size();
+    char hexbuf[len*2 + 1];
+
+    hexbuf[0] = '\0';
+    for (size_t i = 0; i < len; i++) {
+        snprintf(&hexbuf[2*i], 3, "%02x", raw_digest[i]);
+    }
+
+    return name() + "=" + hexbuf;
+}
+
+void sha1_register();
+void sha256_register();
+
+void hash_init()
+{
+    sha1_register();
+    sha256_register();
+}

diff --git a/hash.h b/hash.h
new file mode 100644 (file)
index 0000000..12d5b47
--- /dev/null
+++ b/hash.h
@@ -0,0 +1,65 @@
+/* Cumulus: Smart Filesystem Backup to Dumb Servers
+ *
+ * Copyright (C) 2012  Michael Vrable <vrable@cs.hmc.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/* A generic interface for computing digests of data, used for both
+ * content-based deduplication and for data integrity verification. */
+
+#ifndef CUMULUS_HASH_H
+#define CUMULUS_HASH_H 1
+
+#include <stdint.h>
+#include <string>
+
+/* An object-oriented wrapper around checksumming functionality. */
+class Hash {
+public:
+    Hash() : digest_bytes(NULL) { }
+    virtual ~Hash() { }
+
+    // 
+    virtual void update(const void *data, size_t len) = 0;
+    // Returns the size of the buffer returned by digest, in bytes.
+    virtual size_t digest_size() const = 0;
+    // Returns the name of the hash algorithm.
+    virtual std::string name() const = 0;
+
+    // Calls update with the contents of the data found in the specified file.
+    bool update_from_file(const char *filename);
+    // Finalizes the digest and returns a pointer to a raw byte array
+    // containing the hash.
+    const uint8_t *digest();
+
+    // Returns the digest in text form: "<digest name>=<hex digits>".
+    std::string digest_str();
+
+    //typedef Hash *(*HashConstructor)();
+    static void Register(const std::string& name, Hash *(*constructor)());
+    static Hash *New();
+    static Hash *New(const std::string& name);
+
+protected:
+    virtual const uint8_t *finalize() = 0;
+
+private:
+    const uint8_t *digest_bytes;
+};
+
+void hash_init();
+
+#endif

diff --git a/main.cc b/main.cc
index 297e805..d25788d 100644 (file)
--- a/main.cc
+++ b/main.cc
@@ -49,6 +49,7 @@
 #include <vector>
 
 #include "exclude.h"
+#include "hash.h"
 #include "localdb.h"
 #include "metadata.h"
 #include "remote.h"
@@ -244,7 +245,7 @@ int64_t dumpfile(int fd, dictionary &file_info, const string &path,
     /* If the file is new or changed, we must read in the contents a block at a
      * time. */
     if (!cached) {
-        SHA1Checksum hash;
+        Hash *hash = Hash::New();
         Subfile subfile(db);
         subfile.load_old_blocks(old_blocks);
 
@@ -258,7 +259,7 @@ int64_t dumpfile(int fd, dictionary &file_info, const string &path,
                 break;
             }
 
-            hash.process(block_buf, bytes);
+            hash->update(block_buf, bytes);
 
             // Sparse file processing: if we read a block of all zeroes, encode
             // that explicitly.
@@ -343,7 +344,8 @@ int64_t dumpfile(int fd, dictionary &file_info, const string &path,
                 status = "old";
         }
 
-        file_info["checksum"] = hash.checksum_str();
+        file_info["checksum"] = hash->digest_str();
+        delete hash;
     }
 
     // Sanity check: if we are rebuilding the statcache, but the file looks
@@ -683,6 +685,8 @@ void usage(const char *program)
 
 int main(int argc, char *argv[])
 {
+    hash_init();
+
     string backup_dest = "", backup_script = "";
     string localdb_dir = "";
     string backup_scheme = "";

diff --git a/store.cc b/store.cc
index 9d4c883..f87b671 100644 (file)
--- a/store.cc
+++ b/store.cc
@@ -41,6 +41,7 @@
 #include <string>
 #include <iostream>
 
+#include "hash.h"
 #include "store.h"
 #include "ref.h"
 #include "util.h"
@@ -338,7 +339,8 @@ void LbsObject::checksum()
 {
     assert(written);
 
-    SHA1Checksum hash;
-    hash.process(data, data_len);
-    ref.set_checksum(hash.checksum_str());
+    Hash *hash = Hash::New();
+    hash->update(data, data_len);
+    ref.set_checksum(hash->digest_str());
+    delete hash;
 }

diff --git a/third_party/sha1.cc b/third_party/sha1.cc
index 7111f94..32a6429 100644 (file)
--- a/third_party/sha1.cc
+++ b/third_party/sha1.cc
@@ -27,6 +27,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+#include "../hash.h"
 #include "sha1.h"
 
 #include <stddef.h>
@@ -392,3 +393,40 @@ string SHA1Checksum::checksum_str()
 
     return result;
 }
+
+class SHA1Hash : public Hash {
+public:
+    SHA1Hash();
+    static Hash *New() { return new SHA1Hash; }
+    virtual void update(const void *data, size_t len);
+    virtual size_t digest_size() const { return 20; }
+    virtual std::string name() const { return "sha1"; }
+
+protected:
+    const uint8_t *finalize();
+
+private:
+    struct sha1_ctx ctx;
+    char resbuf[20] __attribute__ ((__aligned__ (__alignof__ (md5_uint32))));
+};
+
+SHA1Hash::SHA1Hash()
+{
+    sha1_init_ctx(&ctx);
+}
+
+void SHA1Hash::update(const void *data, size_t len)
+{
+    sha1_process_bytes(data, len, &ctx);
+}
+
+const uint8_t *SHA1Hash::finalize()
+{
+    sha1_finish_ctx(&ctx, resbuf);
+    return (const uint8_t *)resbuf;
+}
+
+void sha1_register()
+{
+    Hash::Register("sha1", SHA1Hash::New);
+}

diff --git a/third_party/sha256.cc b/third_party/sha256.cc
new file mode 100644 (file)
index 0000000..968b63b
--- /dev/null
+++ b/third_party/sha256.cc
@@ -0,0 +1,439 @@
+/* sha256.cc - Message digests for Cumulus using SHA256
+ *
+ * This code is adapted from crypto/sha256_generic.c and include/crypto/sha.n
+ * from the Linux kernel version 3.4.
+ */
+
+/* SHA-256, as specified in
+ * http://csrc.nist.gov/groups/STM/cavp/documents/shs/sha256-384-512.pdf
+ *
+ * SHA-256 code by Jean-Luc Cooke <jlcooke@certainkey.com>.
+ *
+ * Copyright (c) Jean-Luc Cooke <jlcooke@certainkey.com>
+ * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * SHA224 Support Copyright 2007 Intel Corporation <jonathan.lynch@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option) 
+ * any later version.
+ *
+ */
+
+#define _BSD_SOURCE
+#include <endian.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "../hash.h"
+
+/* Adaptation code for a non-kernel build environment. */
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+static inline u32 ror32(u32 x, int n)
+{
+       return (x >> n) | (x << (32 - n));
+}
+
+static inline u32 cpu_to_be32(u32 x)
+{
+       return htobe32(x);
+}
+
+static inline u64 cpu_to_be64(u64 x)
+{
+       return htobe64(x);
+}
+
+/* Originally from sha.h. */
+
+#define SHA224_DIGEST_SIZE     28
+#define SHA224_BLOCK_SIZE      64
+
+#define SHA256_DIGEST_SIZE      32
+#define SHA256_BLOCK_SIZE       64
+
+#define SHA224_H0      0xc1059ed8UL
+#define SHA224_H1      0x367cd507UL
+#define SHA224_H2      0x3070dd17UL
+#define SHA224_H3      0xf70e5939UL
+#define SHA224_H4      0xffc00b31UL
+#define SHA224_H5      0x68581511UL
+#define SHA224_H6      0x64f98fa7UL
+#define SHA224_H7      0xbefa4fa4UL
+
+#define SHA256_H0      0x6a09e667UL
+#define SHA256_H1      0xbb67ae85UL
+#define SHA256_H2      0x3c6ef372UL
+#define SHA256_H3      0xa54ff53aUL
+#define SHA256_H4      0x510e527fUL
+#define SHA256_H5      0x9b05688cUL
+#define SHA256_H6      0x1f83d9abUL
+#define SHA256_H7      0x5be0cd19UL
+
+struct sha256_state {
+       u64 count;
+       u32 state[SHA256_DIGEST_SIZE / 4];
+       u8 buf[SHA256_BLOCK_SIZE];
+};
+
+/* Originally from sha256_generic.c */
+
+static inline u32 Ch(u32 x, u32 y, u32 z)
+{
+       return z ^ (x & (y ^ z));
+}
+
+static inline u32 Maj(u32 x, u32 y, u32 z)
+{
+       return (x & y) | (z & (x | y));
+}
+
+#define e0(x)       (ror32(x, 2) ^ ror32(x,13) ^ ror32(x,22))
+#define e1(x)       (ror32(x, 6) ^ ror32(x,11) ^ ror32(x,25))
+#define s0(x)       (ror32(x, 7) ^ ror32(x,18) ^ (x >> 3))
+#define s1(x)       (ror32(x,17) ^ ror32(x,19) ^ (x >> 10))
+
+static inline void LOAD_OP(int I, u32 *W, const u8 *input)
+{
+       W[I] = (input[4*I] << 24) | (input[4*I+1] << 16)
+               | (input[4*I+2] << 8) | input[4*I+3];
+}
+
+static inline void BLEND_OP(int I, u32 *W)
+{
+       W[I] = s1(W[I-2]) + W[I-7] + s0(W[I-15]) + W[I-16];
+}
+
+static void sha256_transform(u32 *state, const u8 *input)
+{
+       u32 a, b, c, d, e, f, g, h, t1, t2;
+       u32 W[64];
+       int i;
+
+       /* load the input */
+       for (i = 0; i < 16; i++)
+               LOAD_OP(i, W, input);
+
+       /* now blend */
+       for (i = 16; i < 64; i++)
+               BLEND_OP(i, W);
+
+       /* load the state into our registers */
+       a=state[0];  b=state[1];  c=state[2];  d=state[3];
+       e=state[4];  f=state[5];  g=state[6];  h=state[7];
+
+       /* now iterate */
+       t1 = h + e1(e) + Ch(e,f,g) + 0x428a2f98 + W[ 0];
+       t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+       t1 = g + e1(d) + Ch(d,e,f) + 0x71374491 + W[ 1];
+       t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+       t1 = f + e1(c) + Ch(c,d,e) + 0xb5c0fbcf + W[ 2];
+       t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+       t1 = e + e1(b) + Ch(b,c,d) + 0xe9b5dba5 + W[ 3];
+       t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+       t1 = d + e1(a) + Ch(a,b,c) + 0x3956c25b + W[ 4];
+       t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+       t1 = c + e1(h) + Ch(h,a,b) + 0x59f111f1 + W[ 5];
+       t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+       t1 = b + e1(g) + Ch(g,h,a) + 0x923f82a4 + W[ 6];
+       t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+       t1 = a + e1(f) + Ch(f,g,h) + 0xab1c5ed5 + W[ 7];
+       t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+       t1 = h + e1(e) + Ch(e,f,g) + 0xd807aa98 + W[ 8];
+       t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+       t1 = g + e1(d) + Ch(d,e,f) + 0x12835b01 + W[ 9];
+       t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+       t1 = f + e1(c) + Ch(c,d,e) + 0x243185be + W[10];
+       t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+       t1 = e + e1(b) + Ch(b,c,d) + 0x550c7dc3 + W[11];
+       t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+       t1 = d + e1(a) + Ch(a,b,c) + 0x72be5d74 + W[12];
+       t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+       t1 = c + e1(h) + Ch(h,a,b) + 0x80deb1fe + W[13];
+       t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+       t1 = b + e1(g) + Ch(g,h,a) + 0x9bdc06a7 + W[14];
+       t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+       t1 = a + e1(f) + Ch(f,g,h) + 0xc19bf174 + W[15];
+       t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+       t1 = h + e1(e) + Ch(e,f,g) + 0xe49b69c1 + W[16];
+       t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+       t1 = g + e1(d) + Ch(d,e,f) + 0xefbe4786 + W[17];
+       t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+       t1 = f + e1(c) + Ch(c,d,e) + 0x0fc19dc6 + W[18];
+       t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+       t1 = e + e1(b) + Ch(b,c,d) + 0x240ca1cc + W[19];
+       t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+       t1 = d + e1(a) + Ch(a,b,c) + 0x2de92c6f + W[20];
+       t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+       t1 = c + e1(h) + Ch(h,a,b) + 0x4a7484aa + W[21];
+       t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+       t1 = b + e1(g) + Ch(g,h,a) + 0x5cb0a9dc + W[22];
+       t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+       t1 = a + e1(f) + Ch(f,g,h) + 0x76f988da + W[23];
+       t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+       t1 = h + e1(e) + Ch(e,f,g) + 0x983e5152 + W[24];
+       t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+       t1 = g + e1(d) + Ch(d,e,f) + 0xa831c66d + W[25];
+       t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+       t1 = f + e1(c) + Ch(c,d,e) + 0xb00327c8 + W[26];
+       t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+       t1 = e + e1(b) + Ch(b,c,d) + 0xbf597fc7 + W[27];
+       t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+       t1 = d + e1(a) + Ch(a,b,c) + 0xc6e00bf3 + W[28];
+       t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+       t1 = c + e1(h) + Ch(h,a,b) + 0xd5a79147 + W[29];
+       t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+       t1 = b + e1(g) + Ch(g,h,a) + 0x06ca6351 + W[30];
+       t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+       t1 = a + e1(f) + Ch(f,g,h) + 0x14292967 + W[31];
+       t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+       t1 = h + e1(e) + Ch(e,f,g) + 0x27b70a85 + W[32];
+       t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+       t1 = g + e1(d) + Ch(d,e,f) + 0x2e1b2138 + W[33];
+       t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+       t1 = f + e1(c) + Ch(c,d,e) + 0x4d2c6dfc + W[34];
+       t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+       t1 = e + e1(b) + Ch(b,c,d) + 0x53380d13 + W[35];
+       t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+       t1 = d + e1(a) + Ch(a,b,c) + 0x650a7354 + W[36];
+       t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+       t1 = c + e1(h) + Ch(h,a,b) + 0x766a0abb + W[37];
+       t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+       t1 = b + e1(g) + Ch(g,h,a) + 0x81c2c92e + W[38];
+       t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+       t1 = a + e1(f) + Ch(f,g,h) + 0x92722c85 + W[39];
+       t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+       t1 = h + e1(e) + Ch(e,f,g) + 0xa2bfe8a1 + W[40];
+       t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+       t1 = g + e1(d) + Ch(d,e,f) + 0xa81a664b + W[41];
+       t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+       t1 = f + e1(c) + Ch(c,d,e) + 0xc24b8b70 + W[42];
+       t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+       t1 = e + e1(b) + Ch(b,c,d) + 0xc76c51a3 + W[43];
+       t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+       t1 = d + e1(a) + Ch(a,b,c) + 0xd192e819 + W[44];
+       t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+       t1 = c + e1(h) + Ch(h,a,b) + 0xd6990624 + W[45];
+       t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+       t1 = b + e1(g) + Ch(g,h,a) + 0xf40e3585 + W[46];
+       t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+       t1 = a + e1(f) + Ch(f,g,h) + 0x106aa070 + W[47];
+       t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+       t1 = h + e1(e) + Ch(e,f,g) + 0x19a4c116 + W[48];
+       t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+       t1 = g + e1(d) + Ch(d,e,f) + 0x1e376c08 + W[49];
+       t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+       t1 = f + e1(c) + Ch(c,d,e) + 0x2748774c + W[50];
+       t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+       t1 = e + e1(b) + Ch(b,c,d) + 0x34b0bcb5 + W[51];
+       t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+       t1 = d + e1(a) + Ch(a,b,c) + 0x391c0cb3 + W[52];
+       t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+       t1 = c + e1(h) + Ch(h,a,b) + 0x4ed8aa4a + W[53];
+       t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+       t1 = b + e1(g) + Ch(g,h,a) + 0x5b9cca4f + W[54];
+       t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+       t1 = a + e1(f) + Ch(f,g,h) + 0x682e6ff3 + W[55];
+       t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+       t1 = h + e1(e) + Ch(e,f,g) + 0x748f82ee + W[56];
+       t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+       t1 = g + e1(d) + Ch(d,e,f) + 0x78a5636f + W[57];
+       t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+       t1 = f + e1(c) + Ch(c,d,e) + 0x84c87814 + W[58];
+       t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+       t1 = e + e1(b) + Ch(b,c,d) + 0x8cc70208 + W[59];
+       t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+       t1 = d + e1(a) + Ch(a,b,c) + 0x90befffa + W[60];
+       t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+       t1 = c + e1(h) + Ch(h,a,b) + 0xa4506ceb + W[61];
+       t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+       t1 = b + e1(g) + Ch(g,h,a) + 0xbef9a3f7 + W[62];
+       t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+       t1 = a + e1(f) + Ch(f,g,h) + 0xc67178f2 + W[63];
+       t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+       state[0] += a; state[1] += b; state[2] += c; state[3] += d;
+       state[4] += e; state[5] += f; state[6] += g; state[7] += h;
+}
+
+
+static int sha224_init(struct sha256_state *sctx)
+{
+       sctx->state[0] = SHA224_H0;
+       sctx->state[1] = SHA224_H1;
+       sctx->state[2] = SHA224_H2;
+       sctx->state[3] = SHA224_H3;
+       sctx->state[4] = SHA224_H4;
+       sctx->state[5] = SHA224_H5;
+       sctx->state[6] = SHA224_H6;
+       sctx->state[7] = SHA224_H7;
+       sctx->count = 0;
+
+       return 0;
+}
+
+static int sha256_init(struct sha256_state *sctx)
+{
+       sctx->state[0] = SHA256_H0;
+       sctx->state[1] = SHA256_H1;
+       sctx->state[2] = SHA256_H2;
+       sctx->state[3] = SHA256_H3;
+       sctx->state[4] = SHA256_H4;
+       sctx->state[5] = SHA256_H5;
+       sctx->state[6] = SHA256_H6;
+       sctx->state[7] = SHA256_H7;
+       sctx->count = 0;
+
+       return 0;
+}
+
+static int sha256_update(struct sha256_state *sctx, const u8 *data,
+                        unsigned int len)
+{
+       unsigned int partial, done;
+       const u8 *src;
+
+       partial = sctx->count & 0x3f;
+       sctx->count += len;
+       done = 0;
+       src = data;
+
+       if ((partial + len) > 63) {
+               if (partial) {
+                       done = -partial;
+                       memcpy(sctx->buf + partial, data, done + 64);
+                       src = sctx->buf;
+               }
+
+               do {
+                       sha256_transform(sctx->state, src);
+                       done += 64;
+                       src = data + done;
+               } while (done + 63 < len);
+
+               partial = 0;
+       }
+       memcpy(sctx->buf + partial, src, len - done);
+
+       return 0;
+}
+
+static int sha256_final(struct sha256_state *sctx, u32 *dst)
+{
+       //__be64 bits;
+       u64 bits;
+       unsigned int index, pad_len;
+       int i;
+       static const u8 padding[64] = { 0x80, };
+
+       /* Save number of bits */
+       bits = cpu_to_be64(sctx->count << 3);
+
+       /* Pad out to 56 mod 64. */
+       index = sctx->count & 0x3f;
+       pad_len = (index < 56) ? (56 - index) : ((64+56) - index);
+       sha256_update(sctx, padding, pad_len);
+
+       /* Append length (before padding) */
+       sha256_update(sctx, (const u8 *)&bits, sizeof(bits));
+
+       /* Store state in digest */
+       for (i = 0; i < 8; i++)
+               dst[i] = cpu_to_be32(sctx->state[i]);
+
+       return 0;
+}
+
+static int sha224_final(struct sha256_state *sctx, u32 *hash)
+{
+       u32 D[SHA256_DIGEST_SIZE / 4];
+
+       sha256_final(sctx, D);
+
+       memcpy(hash, D, SHA224_DIGEST_SIZE);
+
+       return 0;
+}
+
+class SHA256Hash : public Hash {
+public:
+    SHA256Hash();
+    static Hash *New() { return new SHA256Hash; }
+    virtual void update(const void *data, size_t len);
+    virtual size_t digest_size() const { return SHA256_DIGEST_SIZE; }
+    virtual std::string name() const { return "sha256"; }
+
+protected:
+    const uint8_t *finalize();
+
+private:
+    struct sha256_state state;
+    u32 digest_buf[SHA256_DIGEST_SIZE / 4];
+};
+
+SHA256Hash::SHA256Hash()
+{
+    sha256_init(&state);
+}
+
+void SHA256Hash::update(const void *data, size_t len)
+{
+    sha256_update(&state, static_cast<const u8 *>(data), len);
+}
+
+const uint8_t *SHA256Hash::finalize()
+{
+    sha256_final(&state, digest_buf);
+    return reinterpret_cast<uint8_t *>(digest_buf);
+}
+
+class SHA224Hash : public Hash {
+public:
+    SHA224Hash();
+    static Hash *New() { return new SHA224Hash; }
+    virtual void update(const void *data, size_t len);
+    virtual size_t digest_size() const { return SHA224_DIGEST_SIZE; }
+    virtual std::string name() const { return "sha224"; }
+
+protected:
+    const uint8_t *finalize();
+
+private:
+    struct sha256_state state;
+    u32 digest_buf[SHA224_DIGEST_SIZE / 4];
+};
+
+SHA224Hash::SHA224Hash()
+{
+    sha224_init(&state);
+}
+
+void SHA224Hash::update(const void *data, size_t len)
+{
+    sha256_update(&state, static_cast<const u8 *>(data), len);
+}
+
+const uint8_t *SHA224Hash::finalize()
+{
+    sha224_final(&state, digest_buf);
+    return reinterpret_cast<uint8_t *>(digest_buf);
+}
+
+void sha256_register()
+{
+    Hash::Register("sha224", SHA224Hash::New);
+    Hash::Register("sha256", SHA256Hash::New);
+}