libcephfs_proxy: fix protocol structures for backward compatibility

The structures used for transferring data between the proxy client and
the proxy daemon had been reworked in a recent change to be able to
expand the protocol. This caused an inconsistency in the size of the
data transferred when communication with a peer using the older version.
The result was that the peer receiving the data with an unexpected size
was closing the connection, causing unexpected errors.

The discrepancy in size is the result of how compilers pad structures
combined with the change in the structure layout introduced when
extending the protocol. With these changes, the computation of the size
of each version of the structures was not done correctly.

This change makes the layout equal to the older version, so that
computing the size of the structures becomes easier and doesn't depend
on unexpected paddings.

Fixes: https://tracker.ceph.com/issues/72800
Signed-off-by: Xavi Hernandez <xhernandez@gmail.com>
(cherry picked from commit 62e917148496bce299f4cd48342765b73b9950a8)

diff --git a/src/libcephfs_proxy/proxy_requests.h b/src/libcephfs_proxy/proxy_requests.h
index 44238f81b65f6f7a9f4fa30967bae3696a5fd154..552e7dd816bf2ad1443ac9301b39053b98f8ffc7 100644 (file)
--- a/src/libcephfs_proxy/proxy_requests.h
+++ b/src/libcephfs_proxy/proxy_requests.h
@@ -39,8 +39,7 @@
        })
 
 #define PROTO_VERSION_SIZE_EXPAND(_data, _ver) \
-       (offset_of(__typeof__(_data), v##_ver) + \
-        field_size(__typeof__(_data), v##_ver))
+       field_size(__typeof__(_data), v##_ver)
 
 #define PROTO_VERSION_SIZE(_data, _ver) PROTO_VERSION_SIZE_EXPAND(_data, _ver)
 
@@ -154,9 +153,57 @@ typedef union {
 #define PROTO_ANS(_fields...) _fields
 #define PROTO_CBK(_fields...) _fields
 
-#define PROTO_VER(_name, _fields...) struct { _fields } _name
-
-#define PROTO_TYPE(_name, _fields...) typedef struct { _fields } _name
+#define PROTO_VER(_name, _fields) _fields, _name
+
+#define PROTO_STRUCT(_name, _fields) \
+       struct { \
+               _fields \
+       } _name;
+
+#define PROTO_VOID(_a...)
+
+#define PROTO_STRUCT_COND_SELECT(_a, _b, _c, _d...) _c
+
+/* This macro outputs a version structure only if the "name" is present.
+ * Otherwise it returns empty.
+ *
+ * Following this macro call, it's expected to find the normal arguments for
+ * a PROTO_STRUCT() macro.
+ *
+ * Example: PROTO_STRUCT_COND(name)(name, fields) */
+#define PROTO_STRUCT_COND(_name...) \
+       PROTO_STRUCT_COND_SELECT(, ## _name, PROTO_STRUCT, PROTO_VOID)
+
+/* These macros are prepared to create up to 4 version structures. If more are
+ * needed, just create a PROTO_BUILD_5 similar to PROTO_BUILD_4 and call it
+ * from PROTO_TYPE.
+ *
+ * The last version of the structure is also declared as an anonymous
+ * substructure to make access to the fields safer and cleaner.
+ *
+ * This approach is needed to be able to define full structures for each
+ * protocol version (i.e. v1 structure also contains all fields from v0), but
+ * without having to explicitly write them in the protocol definitions. This
+ * prevents a lot of copy&paste, it's less error prone, and makes the protocol
+ * extensions cleaner. */
+#define PROTO_BUILD_1(_fields, _name) \
+       PROTO_STRUCT_COND(_name)(_name, _fields) \
+       PROTO_STRUCT(,_fields)
+
+#define PROTO_BUILD_2(_fields, _name, _more...) \
+       PROTO_STRUCT_COND(_name)(_name, _fields) \
+       PROTO_BUILD_1(_fields _more,)
+
+#define PROTO_BUILD_3(_fields, _name, _more...) \
+       PROTO_STRUCT_COND(_name)(_name, _fields) \
+       PROTO_BUILD_2(_fields _more,)
+
+#define PROTO_BUILD_4(_fields, _name, _more...) \
+       PROTO_STRUCT_COND(_name)(_name, _fields) \
+       PROTO_BUILD_3(_fields _more,)
+
+#define PROTO_TYPE(_name, _fields...) \
+       typedef union { PROTO_BUILD_4(_fields) } _name
 
 #define PROTO_CALL(_name, _req, _ans) \
        PROTO_TYPE(proxy_##_name##_req_t, proxy_link_req_t header; _req); \
@@ -170,7 +217,7 @@ typedef union {
 PROTO_CALL(ceph_version,
        PROTO_REQ(
                PROTO_VER(v0,
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
@@ -178,7 +225,7 @@ PROTO_CALL(ceph_version,
                        int32_t minor;
                        int32_t patch;
                        int16_t text;
-               );
+               )
        )
 );
 
@@ -188,12 +235,12 @@ PROTO_CALL(ceph_userperm_new,
                        uint32_t uid;
                        uint32_t gid;
                        uint32_t groups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint64_t userperm;
-               );
+               )
        )
 );
 
@@ -201,11 +248,11 @@ PROTO_CALL(ceph_userperm_destroy,
        PROTO_REQ(
                PROTO_VER(v0,
                        uint64_t userperm;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -213,12 +260,12 @@ PROTO_CALL(ceph_create,
        PROTO_REQ(
                PROTO_VER(v0,
                        int16_t id;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint64_t cmount;
-               );
+               )
        )
 );
 
@@ -226,11 +273,11 @@ PROTO_CALL(ceph_release,
        PROTO_REQ(
                PROTO_VER(v0,
                        uint64_t cmount;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -239,11 +286,11 @@ PROTO_CALL(ceph_conf_read_file,
                PROTO_VER(v0,
                        uint64_t cmount;
                        uint16_t path;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -253,12 +300,12 @@ PROTO_CALL(ceph_conf_get,
                        uint64_t cmount;
                        uint32_t size;
                        uint16_t option;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint16_t value;
-               );
+               )
        )
 );
 
@@ -268,11 +315,11 @@ PROTO_CALL(ceph_conf_set,
                        uint64_t cmount;
                        uint16_t option;
                        uint16_t value;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -280,11 +327,11 @@ PROTO_CALL(ceph_init,
        PROTO_REQ(
                PROTO_VER(v0,
                        uint64_t cmount;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -293,11 +340,11 @@ PROTO_CALL(ceph_select_filesystem,
                PROTO_VER(v0,
                        uint64_t cmount;
                        uint16_t fs;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -306,11 +353,11 @@ PROTO_CALL(ceph_mount,
                PROTO_VER(v0,
                        uint64_t cmount;
                        uint16_t root;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -318,11 +365,11 @@ PROTO_CALL(ceph_unmount,
        PROTO_REQ(
                PROTO_VER(v0,
                        uint64_t cmount;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -331,11 +378,11 @@ PROTO_CALL(ceph_ll_statfs,
                PROTO_VER(v0,
                        uint64_t cmount;
                        uint64_t inode;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -348,15 +395,15 @@ PROTO_CALL(ceph_ll_lookup,
                        uint32_t want;
                        uint32_t flags;
                        uint16_t name;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint64_t inode;
-               );
+               )
        )
 );
 
@@ -365,12 +412,12 @@ PROTO_CALL(ceph_ll_lookup_inode,
                PROTO_VER(v0,
                        uint64_t cmount;
                        struct inodeno_t ino;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint64_t inode;
-               );
+               )
        )
 );
 
@@ -378,12 +425,12 @@ PROTO_CALL(ceph_ll_lookup_root,
        PROTO_REQ(
                PROTO_VER(v0,
                        uint64_t cmount;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint64_t inode;
-               );
+               )
        )
 );
 
@@ -392,11 +439,11 @@ PROTO_CALL(ceph_ll_put,
                PROTO_VER(v0,
                        uint64_t cmount;
                        uint64_t inode;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -408,15 +455,15 @@ PROTO_CALL(ceph_ll_walk,
                        uint32_t want;
                        uint32_t flags;
                        uint16_t path;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint64_t inode;
-               );
+               )
        )
 );
 
@@ -425,11 +472,11 @@ PROTO_CALL(ceph_chdir,
                PROTO_VER(v0,
                        uint64_t cmount;
                        uint16_t path;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -437,12 +484,12 @@ PROTO_CALL(ceph_getcwd,
        PROTO_REQ(
                PROTO_VER(v0,
                        uint64_t cmount;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint16_t path;
-               );
+               )
        )
 );
 
@@ -451,12 +498,12 @@ PROTO_CALL(ceph_readdir,
                PROTO_VER(v0,
                        uint64_t cmount;
                        uint64_t dir;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        bool eod;
-               );
+               )
        )
 );
 
@@ -465,11 +512,11 @@ PROTO_CALL(ceph_rewinddir,
                PROTO_VER(v0,
                        uint64_t cmount;
                        uint64_t dir;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -480,15 +527,15 @@ PROTO_CALL(ceph_ll_open,
                        embedded_perms_t userperm;
                        uint64_t inode;
                        int32_t flags;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint64_t fh;
-               );
+               )
        )
 );
 
@@ -503,16 +550,16 @@ PROTO_CALL(ceph_ll_create,
                        uint32_t want;
                        uint32_t flags;
                        uint16_t name;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint64_t inode;
                        uint64_t fh;
-               );
+               )
        )
 );
 
@@ -527,15 +574,15 @@ PROTO_CALL(ceph_ll_mknod,
                        uint32_t want;
                        uint32_t flags;
                        uint16_t name;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint64_t inode;
-               );
+               )
        )
 );
 
@@ -544,11 +591,11 @@ PROTO_CALL(ceph_ll_close,
                PROTO_VER(v0,
                        uint64_t cmount;
                        uint64_t fh;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -561,14 +608,14 @@ PROTO_CALL(ceph_ll_rename,
                        uint64_t new_parent;
                        uint16_t old_name;
                        uint16_t new_name;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -579,12 +626,12 @@ PROTO_CALL(ceph_ll_lseek,
                        uint64_t fh;
                        off_t offset;
                        int32_t whence;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        off_t offset;
-               );
+               )
        )
 );
 
@@ -595,11 +642,11 @@ PROTO_CALL(ceph_ll_read,
                        uint64_t fh;
                        int64_t offset;
                        uint64_t len;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -610,11 +657,11 @@ PROTO_CALL(ceph_ll_write,
                        uint64_t fh;
                        int64_t offset;
                        uint64_t len;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -626,14 +673,14 @@ PROTO_CALL(ceph_ll_link,
                        uint64_t inode;
                        uint64_t parent;
                        uint16_t name;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -644,14 +691,14 @@ PROTO_CALL(ceph_ll_unlink,
                        embedded_perms_t userperm;
                        uint64_t parent;
                        uint16_t name;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -663,14 +710,14 @@ PROTO_CALL(ceph_ll_getattr,
                        uint64_t inode;
                        uint32_t want;
                        uint32_t flags;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -681,14 +728,14 @@ PROTO_CALL(ceph_ll_setattr,
                        embedded_perms_t userperm;
                        uint64_t inode;
                        int32_t mask;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -700,11 +747,11 @@ PROTO_CALL(ceph_ll_fallocate,
                        int64_t offset;
                        int64_t length;
                        int32_t mode;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -714,11 +761,11 @@ PROTO_CALL(ceph_ll_fsync,
                        uint64_t cmount;
                        uint64_t fh;
                        int32_t dataonly;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -729,15 +776,15 @@ PROTO_CALL(ceph_ll_listxattr,
                        embedded_perms_t userperm;
                        uint64_t inode;
                        size_t size;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        size_t size;
-               );
+               )
        )
 );
 
@@ -749,14 +796,14 @@ PROTO_CALL(ceph_ll_getxattr,
                        uint64_t inode;
                        size_t size;
                        uint16_t name;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -769,14 +816,14 @@ PROTO_CALL(ceph_ll_setxattr,
                        size_t size;
                        int32_t flags;
                        uint16_t name;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -787,14 +834,14 @@ PROTO_CALL(ceph_ll_removexattr,
                        embedded_perms_t userperm;
                        uint64_t inode;
                        uint16_t name;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -805,14 +852,14 @@ PROTO_CALL(ceph_ll_readlink,
                        embedded_perms_t userperm;
                        uint64_t inode;
                        size_t size;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -826,15 +873,15 @@ PROTO_CALL(ceph_ll_symlink,
                        uint32_t flags;
                        uint16_t name;
                        uint16_t target;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint64_t inode;
-               );
+               )
        )
 );
 
@@ -844,15 +891,15 @@ PROTO_CALL(ceph_ll_opendir,
                        uint64_t cmount;
                        embedded_perms_t userperm;
                        uint64_t inode;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint64_t dir;
-               );
+               )
        )
 );
 
@@ -866,15 +913,15 @@ PROTO_CALL(ceph_ll_mkdir,
                        uint32_t want;
                        uint32_t flags;
                        uint16_t name;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint64_t inode;
-               );
+               )
        )
 );
 
@@ -885,14 +932,14 @@ PROTO_CALL(ceph_ll_rmdir,
                        embedded_perms_t userperm;
                        uint64_t parent;
                        uint16_t name;
-               );
+               ),
                PROTO_VER(v1,
                        uint32_t ngroups;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -901,11 +948,11 @@ PROTO_CALL(ceph_ll_releasedir,
                PROTO_VER(v0,
                        uint64_t cmount;
                        uint64_t dir;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
-               );
+               )
        )
 );
 
@@ -913,12 +960,12 @@ PROTO_CALL(ceph_mount_perms,
        PROTO_REQ(
                PROTO_VER(v0,
                        uint64_t cmount;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        uint64_t userperm;
-               );
+               )
        )
 );
 
@@ -933,12 +980,12 @@ PROTO_CALL(ceph_ll_nonblocking_readv_writev,
                        bool write;
                        bool fsync;
                        bool syncdataonly;
-               );
+               )
        ),
        PROTO_ANS(
                PROTO_VER(v0,
                        int64_t res;
-               );
+               )
        )
 );
 
@@ -1000,7 +1047,7 @@ PROTO_NOTIFY(ceph_ll_nonblocking_readv_writev,
                PROTO_VER(v0,
                        uint64_t info;
                        int64_t res;
-               );
+               )
        )
 );