features/uss: Use xxh64 to generate gfid instead of md5sum

* This is to ensure FIPS support
* Also changed the signature of svs_uuid_generate to
  get xlator argument
* Added xxh64 wrapper functions in common-utils to
  generate gfid using xxh64
  - Those wrapper functions can be used by other xlators
    as well to generate gfids using xxh64. But as of now
    snapview-server is going to be the only consumer.

Change-Id: Ide66573125dd74122430cccc4c4dc2a376d642a2
Updates: #230
Signed-off-by: Raghavendra Manjunath <raghavendra@redhat.com>
Signed-off-by: Raghavendra Bhat <raghavendra@redhat.com>

7 files changed, 219 insertions, 14 deletions

diff --git a/libglusterfs/src/common-utils.c b/libglusterfs/src/common-utils.c
index 4c98e705e5e..748772bb21b 100644
--- a/libglusterfs/src/common-utils.c
+++ b/libglusterfs/src/common-utils.c
@@ -95,6 +95,176 @@ gf_xxh64_wrapper(const unsigned char *data, size_t const len, unsigned long long
                 snprintf(xxh64 + i * 2, lim-i*2, "%02x", p[i]);
 }
 
+/**
+ * This function takes following arguments
+ * @this: xlator
+ * @gfid: The gfid which has to be filled
+ * @hash: the 8 byte hash which has to be filled inside the gfid
+ * @index: the array element of the uuid_t structure (which is
+ *         a array of unsigned char) from where the 8 bytes of
+ *         the hash has to be filled. Since uuid_t contains 16
+ *        char elements in the array, each byte of the hash has
+ *        to be filled in one array element.
+ *
+ * This function is called twice for 2 hashes (of 8 byte each) to
+ * be filled in the gfid.
+ *
+ * The for loop in this function actually is doing these 2 things
+ * for each hash
+ *
+ * 1) One of the hashes
+ *      tmp[0] = (hash_2 >> 56) & 0xff;
+ *      tmp[1] = (hash_2 >> 48) & 0xff;
+ *      tmp[2] = (hash_2 >> 40) & 0xff;
+ *      tmp[3] = (hash_2 >> 32) & 0xff;
+ *      tmp[4] = (hash_2 >> 24) & 0xff;
+ *      tmp[5] = (hash_2 >> 16) & 0xff;
+ *      tmp[6] = (hash_2 >> 8) & 0xff;
+ *      tmp[7] = (hash_2) & 0xff;
+ *
+ * 2) The other hash:
+ *      tmp[8] = (hash_1 >> 56) & 0xff;
+ *      tmp[9] = (hash_1 >> 48) & 0xff;
+ *      tmp[10] = (hash_1 >> 40) & 0xff;
+ *      tmp[11] = (hash_1 >> 32) & 0xff;
+ *      tmp[12] = (hash_1 >> 24) & 0xff;
+ *      tmp[13] = (hash_1 >> 16) & 0xff;
+ *      tmp[14] = (hash_1 >> 8) & 0xff;
+ *      tmp[15] = (hash_1) & 0xff;
+ **/
+static int
+gf_gfid_from_xxh64 (xlator_t *this, uuid_t gfid, XXH64_hash_t hash,
+                    unsigned short index)
+{
+        int ret = -1;
+        int i   = -1;
+
+        if ((index != 0) && (index != 8)) {
+                gf_msg_callingfn ("gfid-from-xxh64", GF_LOG_WARNING, 0,
+                                  LG_MSG_INDEX_NOT_FOUND,
+                                  "index can only be either 0 or 8, as this"
+                                  "function's purpose is to encode a 8 byte "
+                                  "hash inside the gfid (index: %d)", index);
+                goto out;
+        }
+
+        for (i = 0; i < sizeof (hash); i++) {
+                /*
+                 * As of now the below statement is equivalent of this.
+                 * gfid[index+i] = (hash >> (64 - (8 * (i+1)))) & 0xff;
+                 */
+                gfid[index+i] = (hash >> ((sizeof (hash) * 8) - (8 * (i+1))))
+                                & (0xff);
+        }
+
+        ret = 0;
+
+out:
+        return ret;
+}
+
+/**
+ * This function does the same thing as gf_xxh64_wrapper. But gf_xxh64_wrapper
+ * does not return anything and in this xlator there is a need for both the
+ * actual hash and the canonicalized form of the hash.
+ *
+ * To summarize:
+ * - XXH64_hash_t is needed as return because, those bytes which contain the
+ *   hash can be used for different purposes as needed. One example is
+ *   to have those bytes copied into the uuid_t structure to be used as gfid
+ * - xxh64 string is needed because, it can be used as the key for generating
+ *   the next hash (and any other purpose which might require canonical form
+ *   of the hash).
+ **/
+XXH64_hash_t
+gf_xxh64_hash_wrapper (const unsigned char *data, size_t const len,
+                       unsigned long long const seed, char *xxh64)
+{
+        unsigned short         i      = 0;
+        const unsigned short   lim    = GF_XXH64_DIGEST_LENGTH*2+1;
+        XXH64_hash_t           hash   = 0;
+        XXH64_canonical_t      c_hash = {{0,},};
+        const uint8_t          *p     = (const uint8_t *)&c_hash;
+
+        hash = XXH64(data, len, seed);
+        XXH64_canonicalFromHash (&c_hash, hash);
+
+        for (i = 0; i < GF_XXH64_DIGEST_LENGTH; i++)
+                snprintf (xxh64 + i * 2, lim-i*2, "%02x", p[i]);
+
+        return hash;
+}
+
+/**
+ * This is the algorithm followed for generating new gfid
+ * 1) generate xxh64 hash using snapname and original gfid of the object
+ * 2) Using the canonicalized form of above hash as the key, generate
+ *    another hash
+ * 3) Combine both of the  8 byte hashes to generate a 16 byte uuid_t type
+ * 4) Use the above uuid as the gfid
+ *
+ * Each byte of the hash is stored separately in different elements of the
+ * character array represented by uuid_t
+ * Ex: tmp[0] = (hash_2 >> 56) & 0xFF
+ *     This saves the most significant byte of hash_2 in tmp[0]
+ *     tmp[1] = (hash_2 >> 48) & 0xFF
+ *     This saves next most significant byte of hash_2 in tmp[1]
+ *     .
+ *     .
+ *     So on.
+ *     tmp[0] - tmp[7] holds the contents of hash_2
+ *     tmp[8] - tmp[15] hold the conents of hash_1
+ *
+ * The hash generated (i.e. of type XXH64_hash_t) is 8 bytes long. And for
+ * gfid 16 byte uuid is needed. Hecne the 2 hashes are combined to form
+ * one 16 byte entity.
+ **/
+int
+gf_gfid_generate_from_xxh64 (uuid_t gfid, char *key)
+{
+        char xxh64_1[GF_XXH64_DIGEST_LENGTH*2+1] = {0, };
+        char xxh64_2[GF_XXH64_DIGEST_LENGTH*2+1] = {0, };
+        XXH64_hash_t hash_1                      = 0;
+        XXH64_hash_t hash_2                      = 0;
+        int          ret                         = -1;
+        xlator_t    *this                        = THIS;
+
+        hash_1 = gf_xxh64_hash_wrapper((unsigned char *)key,
+                                       strlen (key), GF_XXHSUM64_DEFAULT_SEED,
+                                       xxh64_1);
+
+        hash_2 = gf_xxh64_hash_wrapper((unsigned char *)xxh64_1,
+                                       strlen (xxh64_1),
+                                       GF_XXHSUM64_DEFAULT_SEED, xxh64_2);
+
+        /* hash_2 is saved in 1st 8 elements of uuid_t char array */
+        if (gf_gfid_from_xxh64 (this, gfid, hash_2, 0)) {
+                gf_msg_callingfn (this->name, GF_LOG_WARNING, 0,
+                                  LG_MSG_XXH64_TO_GFID_FAILED,
+                                  "failed to encode the hash %llx into the 1st"
+                                  "half of gfid", hash_2);
+                goto out;
+        }
+
+        /* hash_1 is saved in the remaining 8 elements of uuid_t */
+        if (gf_gfid_from_xxh64 (this, gfid, hash_1, 8)) {
+                gf_msg_callingfn (this->name, GF_LOG_WARNING, 0,
+                                  LG_MSG_XXH64_TO_GFID_FAILED,
+                                  "failed to encode the hash %llx into the 2nd"
+                                  "half of gfid", hash_1);
+                goto out;
+        }
+
+        gf_msg_debug (this->name, 0, "gfid generated is %s (hash1: %llx) "
+                      "hash2: %llx, xxh64_1: %s xxh64_2: %s", uuid_utoa (gfid),
+                      hash_1, hash_2, xxh64_1, xxh64_2);
+
+        ret = 0;
+
+out:
+        return ret;
+}
+
 /* works similar to mkdir(1) -p.
  */
 int
diff --git a/libglusterfs/src/common-utils.h b/libglusterfs/src/common-utils.h
index 4fd92b0315b..ef09ca5a337 100644
--- a/libglusterfs/src/common-utils.h
+++ b/libglusterfs/src/common-utils.h
@@ -855,6 +855,8 @@ gf_boolean_t gf_is_local_addr (char *hostname);
 gf_boolean_t gf_is_same_address (char *host1, char *host2);
 void gf_xxh64_wrapper(const unsigned char *data, size_t const len,
                       unsigned long long const seed, char *xxh64);
+int gf_gfid_generate_from_xxh64 (uuid_t gfid, char *key);
+
 int gf_set_timestamp  (const char *src, const char* dest);
 
 int gf_thread_create (pthread_t *thread, const pthread_attr_t *attr,
diff --git a/libglusterfs/src/libglusterfs-messages.h b/libglusterfs/src/libglusterfs-messages.h
index ad7d69e6b4c..66e92f2b8f1 100644
--- a/libglusterfs/src/libglusterfs-messages.h
+++ b/libglusterfs/src/libglusterfs-messages.h
@@ -235,7 +235,8 @@ GLFS_MSGID(LIBGLUSTERFS,
         LG_MSG_COMPACT_STATUS,
         LG_MSG_UTIMENSAT_FAILED,
         LG_MSG_PTHREAD_NAMING_FAILED,
-        LG_MSG_SYSCALL_RETURNS_WRONG
+        LG_MSG_SYSCALL_RETURNS_WRONG,
+        LG_MSG_XXH64_TO_GFID_FAILED
 );
 
 #endif /* !_LG_MESSAGES_H_ */
diff --git a/libglusterfs/src/libglusterfs.sym b/libglusterfs/src/libglusterfs.sym
index 2da3e701ef9..61a866a3d27 100644
--- a/libglusterfs/src/libglusterfs.sym
+++ b/libglusterfs/src/libglusterfs.sym
@@ -1124,3 +1124,4 @@ gf_replace_old_iatt_in_dict
 gf_replace_new_iatt_in_dict
 gf_changelog_init
 gf_changelog_register_generic
+gf_gfid_generate_from_xxh64
\ No newline at end of file
diff --git a/xlators/features/snapview-server/src/snapview-server-helpers.c b/xlators/features/snapview-server/src/snapview-server-helpers.c
index 091feb59180..9e12501807b 100644
--- a/xlators/features/snapview-server/src/snapview-server-helpers.c
+++ b/xlators/features/snapview-server/src/snapview-server-helpers.c
@@ -16,7 +16,6 @@
 #include "protocol-common.h"
 #include <pthread.h>
 
-
 int
 __svs_inode_ctx_set (xlator_t *this, inode_t *inode, svs_inode_t *svs_inode)
 {
@@ -329,18 +328,37 @@ out:
         return svs_fd;
 }
 
-void
-svs_uuid_generate (uuid_t gfid, char *snapname, uuid_t origin_gfid)
+int
+svs_uuid_generate (xlator_t *this, uuid_t gfid, char *snapname,
+                   uuid_t origin_gfid)
 {
-        unsigned char md5_sum[MD5_DIGEST_LENGTH] = {0};
-        char          ino_string[NAME_MAX + 32]  = "";
+        char ino_string[NAME_MAX + 32]  = "";
+        uuid_t tmp = {0, };
+        int    ret = -1;
 
-        GF_ASSERT (snapname);
+        GF_VALIDATE_OR_GOTO ("snapview-server", this, out);
+        GF_VALIDATE_OR_GOTO (this->name, snapname, out);
 
         (void) snprintf (ino_string, sizeof (ino_string), "%s%s",
                          snapname, uuid_utoa(origin_gfid));
-        MD5((unsigned char *)ino_string, strlen(ino_string), md5_sum);
-        gf_uuid_copy (gfid, md5_sum);
+
+        if (gf_gfid_generate_from_xxh64 (tmp, ino_string)) {
+                gf_log (this->name, GF_LOG_WARNING, "failed to generate "
+                        "gfid for object with actual gfid of %s "
+                        "(snapname: %s, key: %s)", uuid_utoa (origin_gfid),
+                        snapname, ino_string);
+                goto out;
+        }
+
+        gf_uuid_copy (gfid, tmp);
+
+        ret = 0;
+
+        gf_log (this->name, GF_LOG_DEBUG, "gfid generated is %s ",
+                uuid_utoa (gfid));
+
+out:
+        return ret;
 }
 
 void
diff --git a/xlators/features/snapview-server/src/snapview-server.c b/xlators/features/snapview-server/src/snapview-server.c
index ed56937aa7c..664889b4a16 100644
--- a/xlators/features/snapview-server/src/snapview-server.c
+++ b/xlators/features/snapview-server/src/snapview-server.c
@@ -323,6 +323,8 @@ svs_lookup_entry (xlator_t *this, loc_t *loc, struct iatt *buf,
         svs_inode_t    *inode_ctx                       = NULL;
         glfs_object_t  *parent_object                   = NULL;
         uuid_t          gfid                            = {0, };
+        int             ret                             = -1;
+
 
         GF_VALIDATE_OR_GOTO ("snapview-server", this, out);
         GF_VALIDATE_OR_GOTO (this->name, loc, out);
@@ -364,9 +366,19 @@ svs_lookup_entry (xlator_t *this, loc_t *loc, struct iatt *buf,
         }
 
         if (gf_uuid_is_null (loc->gfid) &&
-            gf_uuid_is_null (loc->inode->gfid))
-                svs_uuid_generate (gfid, parent_ctx->snapname, object->gfid);
-        else {
+            gf_uuid_is_null (loc->inode->gfid)) {
+                ret = svs_uuid_generate (this, gfid, parent_ctx->snapname,
+                                         object->gfid);
+                /*
+                 * should op_errno be something else such as
+                 * EINVAL or ESTALE?
+                 */
+                if (ret) {
+                        op_ret = -1;
+                        *op_errno = EIO;
+                        goto out;
+                }
+        } else {
                 if (!gf_uuid_is_null (loc->inode->gfid))
                         gf_uuid_copy (gfid, loc->inode->gfid);
                 else
diff --git a/xlators/features/snapview-server/src/snapview-server.h b/xlators/features/snapview-server/src/snapview-server.h
index a805c7435bd..d024a77011b 100644
--- a/xlators/features/snapview-server/src/snapview-server.h
+++ b/xlators/features/snapview-server/src/snapview-server.h
@@ -209,8 +209,9 @@ __svs_fd_ctx_get_or_new (xlator_t *this, fd_t *fd);
 svs_fd_t *
 svs_fd_ctx_get_or_new (xlator_t *this, fd_t *fd);
 
-void
-svs_uuid_generate (uuid_t gfid, char *snapname, uuid_t origin_gfid);
+int
+svs_uuid_generate (xlator_t *this, uuid_t gfid, char *snapname,
+                   uuid_t origin_gfid);
 
 void
 svs_fill_ino_from_gfid (struct iatt *buf);