ceph: buffer decoding helpers

Helper for decoding into a ceph_buffer, and other misc decoding helpers
we will need.

Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>

3 files changed, 53 insertions, 0 deletions

diff --git a/fs/ceph/buffer.c b/fs/ceph/buffer.c
index 2576bd452cb8..b98086c7aeba 100644
--- a/fs/ceph/buffer.c
+++ b/fs/ceph/buffer.c
@@ -1,6 +1,7 @@
 
 #include "ceph_debug.h"
 #include "buffer.h"
+#include "decode.h"
 
 struct ceph_buffer *ceph_buffer_new(size_t len, gfp_t gfp)
 {
@@ -59,3 +60,19 @@ int ceph_buffer_alloc(struct ceph_buffer *b, int len, gfp_t gfp)
         return 0;
 }
 
+int ceph_decode_buffer(struct ceph_buffer **b, void **p, void *end)
+{
+        size_t len;
+
+        ceph_decode_need(p, end, sizeof(u32), bad);
+        len = ceph_decode_32(p);
+        dout("decode_buffer len %d\n", (int)len);
+        ceph_decode_need(p, end, len, bad);
+        *b = ceph_buffer_new(len, GFP_NOFS);
+        if (!*b)
+                return -ENOMEM;
+        ceph_decode_copy(p, (*b)->vec.iov_base, len);
+        return 0;
+bad:
+        return -EINVAL;
+}
diff --git a/fs/ceph/buffer.h b/fs/ceph/buffer.h
index 47b9514c5bbd..58d19014068f 100644
--- a/fs/ceph/buffer.h
+++ b/fs/ceph/buffer.h
@@ -34,4 +34,6 @@ static inline void ceph_buffer_put(struct ceph_buffer *b)
         kref_put(&b->kref, ceph_buffer_release);
 }
 
+extern int ceph_decode_buffer(struct ceph_buffer **b, void **p, void *end);
+
 #endif
diff --git a/fs/ceph/decode.h b/fs/ceph/decode.h
index b90a33b948c7..65b3e022eaf5 100644
--- a/fs/ceph/decode.h
+++ b/fs/ceph/decode.h
@@ -2,6 +2,7 @@
 #define __CEPH_DECODE_H
 
 #include <asm/unaligned.h>
+#include <linux/time.h>
 
 #include "types.h"
 
@@ -65,6 +66,11 @@ static inline void ceph_decode_copy(void **p, void *pv, size_t n)
                 ceph_decode_need(p, end, sizeof(u16), bad);     \
                 v = ceph_decode_16(p);                          \
         } while (0)
+#define ceph_decode_8_safe(p, end, v, bad)                      \
+        do {                                                    \
+                ceph_decode_need(p, end, sizeof(u8), bad);      \
+                v = ceph_decode_8(p);                           \
+        } while (0)
 
 #define ceph_decode_copy_safe(p, end, pv, n, bad)               \
         do {                                                    \
@@ -156,5 +162,33 @@ static inline void ceph_encode_string(void **p, void *end,
         *p += len;
 }
 
+#define ceph_encode_need(p, end, n, bad)                \
+        do {                                            \
+                if (unlikely(*(p) + (n) > (end)))       \
+                        goto bad;                       \
+        } while (0)
+
+#define ceph_encode_64_safe(p, end, v, bad)                     \
+        do {                                                    \
+                ceph_encode_need(p, end, sizeof(u64), bad);     \
+                ceph_encode_64(p, v);                           \
+        } while (0)
+#define ceph_encode_32_safe(p, end, v, bad)                     \
+        do {                                                    \
+                ceph_encode_need(p, end, sizeof(u32), bad);     \
+                ceph_encode_32(p, v);                   \
+        } while (0)
+#define ceph_encode_16_safe(p, end, v, bad)                     \
+        do {                                                    \
+                ceph_encode_need(p, end, sizeof(u16), bad);     \
+                ceph_encode_16(p, v);                   \
+        } while (0)
+
+#define ceph_encode_copy_safe(p, end, pv, n, bad)               \
+        do {                                                    \
+                ceph_encode_need(p, end, n, bad);               \
+                ceph_encode_copy(p, pv, n);                     \
+        } while (0)
+
 
 #endif