ceph: on-wire types
These headers describe the types used to exchange messages between the
Ceph client and various servers. All types are little-endian and
packed. These headers are shared between the kernel and userspace, so
all types are in terms of e.g. __u32.
Additionally, we define a few magic values to identify the current
version of the protocol(s) in use, so that discrepancies to be
detected on mount.
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/msgr.h b/fs/ceph/msgr.h
new file mode 100644
index 0000000..73921ae
--- /dev/null
+++ b/fs/ceph/msgr.h
@@ -0,0 +1,157 @@
+#ifndef __MSGR_H
+#define __MSGR_H
+
+/*
+ * Data types for message passing layer used by Ceph.
+ */
+
+#define CEPH_MON_PORT 6789 /* default monitor port */
+
+/*
+ * client-side processes will try to bind to ports in this
+ * range, simply for the benefit of tools like nmap or wireshark
+ * that would like to identify the protocol.
+ */
+#define CEPH_PORT_FIRST 6789
+#define CEPH_PORT_START 6800 /* non-monitors start here */
+#define CEPH_PORT_LAST 6900
+
+/*
+ * tcp connection banner. include a protocol version. and adjust
+ * whenever the wire protocol changes. try to keep this string length
+ * constant.
+ */
+#define CEPH_BANNER "ceph v021"
+#define CEPH_BANNER_MAX_LEN 30
+
+
+/*
+ * Rollover-safe type and comparator for 32-bit sequence numbers.
+ * Comparator returns -1, 0, or 1.
+ */
+typedef __u32 ceph_seq_t;
+
+static inline __s32 ceph_seq_cmp(__u32 a, __u32 b)
+{
+ return (__s32)a - (__s32)b;
+}
+
+
+/*
+ * entity_name -- logical name for a process participating in the
+ * network, e.g. 'mds0' or 'osd3'.
+ */
+struct ceph_entity_name {
+ __u8 type; /* CEPH_ENTITY_TYPE_* */
+ __le64 num;
+} __attribute__ ((packed));
+
+#define CEPH_ENTITY_TYPE_MON 1
+#define CEPH_ENTITY_TYPE_MDS 2
+#define CEPH_ENTITY_TYPE_OSD 3
+#define CEPH_ENTITY_TYPE_CLIENT 4
+#define CEPH_ENTITY_TYPE_ADMIN 5
+
+/*
+ * entity_addr -- network address
+ */
+struct ceph_entity_addr {
+ __le32 erank; /* entity's rank in process */
+ __le32 nonce; /* unique id for process (e.g. pid) */
+ struct sockaddr_storage in_addr;
+} __attribute__ ((packed));
+
+static inline bool ceph_entity_addr_is_local(const struct ceph_entity_addr *a,
+ const struct ceph_entity_addr *b)
+{
+ return a->nonce == b->nonce &&
+ memcmp(&a->in_addr, &b->in_addr, sizeof(a->in_addr)) == 0;
+}
+
+static inline bool ceph_entity_addr_equal(const struct ceph_entity_addr *a,
+ const struct ceph_entity_addr *b)
+{
+ return memcmp(a, b, sizeof(*a)) == 0;
+}
+
+struct ceph_entity_inst {
+ struct ceph_entity_name name;
+ struct ceph_entity_addr addr;
+} __attribute__ ((packed));
+
+
+/* used by message exchange protocol */
+#define CEPH_MSGR_TAG_READY 1 /* server->client: ready for messages */
+#define CEPH_MSGR_TAG_RESETSESSION 2 /* server->client: reset, try again */
+#define CEPH_MSGR_TAG_WAIT 3 /* server->client: wait for racing
+ incoming connection */
+#define CEPH_MSGR_TAG_RETRY_SESSION 4 /* server->client + cseq: try again
+ with higher cseq */
+#define CEPH_MSGR_TAG_RETRY_GLOBAL 5 /* server->client + gseq: try again
+ with higher gseq */
+#define CEPH_MSGR_TAG_CLOSE 6 /* closing pipe */
+#define CEPH_MSGR_TAG_MSG 7 /* message */
+#define CEPH_MSGR_TAG_ACK 8 /* message ack */
+#define CEPH_MSGR_TAG_KEEPALIVE 9 /* just a keepalive byte! */
+#define CEPH_MSGR_TAG_BADPROTOVER 10 /* bad protocol version */
+
+
+/*
+ * connection negotiation
+ */
+struct ceph_msg_connect {
+ __le32 host_type; /* CEPH_ENTITY_TYPE_* */
+ __le32 global_seq; /* count connections initiated by this host */
+ __le32 connect_seq; /* count connections initiated in this session */
+ __le32 protocol_version;
+ __u8 flags; /* CEPH_MSG_CONNECT_* */
+} __attribute__ ((packed));
+
+struct ceph_msg_connect_reply {
+ __u8 tag;
+ __le32 global_seq;
+ __le32 connect_seq;
+ __le32 protocol_version;
+ __u8 flags;
+} __attribute__ ((packed));
+
+#define CEPH_MSG_CONNECT_LOSSY 1 /* messages i send may be safely dropped */
+
+
+/*
+ * message header
+ */
+struct ceph_msg_header {
+ __le64 seq; /* message seq# for this session */
+ __le16 type; /* message type */
+ __le16 priority; /* priority. higher value == higher priority */
+
+ __le32 front_len; /* bytes in main payload */
+ __le32 middle_len;/* bytes in middle payload */
+ __le32 data_len; /* bytes of data payload */
+ __le16 data_off; /* sender: include full offset;
+ receiver: mask against ~PAGE_MASK */
+
+ struct ceph_entity_inst src, orig_src;
+ __le32 dst_erank;
+ __le32 crc; /* header crc32c */
+} __attribute__ ((packed));
+
+#define CEPH_MSG_PRIO_LOW 64
+#define CEPH_MSG_PRIO_DEFAULT 127
+#define CEPH_MSG_PRIO_HIGH 196
+#define CEPH_MSG_PRIO_HIGHEST 255
+
+/*
+ * follows data payload
+ */
+struct ceph_msg_footer {
+ __le32 front_crc, middle_crc, data_crc;
+ __u8 flags;
+} __attribute__ ((packed));
+
+#define CEPH_MSG_FOOTER_COMPLETE (1<<0) /* msg wasn't aborted */
+#define CEPH_MSG_FOOTER_NOCRC (1<<1) /* no data crc */
+
+
+#endif