2 files changed, 590 insertions, 1 deletions

diff --git a/include/linux/connector.h b/include/linux/connector.h
index fc65d219d88c..b9966e64604e 100644
--- a/include/linux/connector.h
+++ b/include/linux/connector.h
@@ -39,8 +39,10 @@
 #define CN_IDX_V86D                     0x4
 #define CN_VAL_V86D_UVESAFB             0x1
 #define CN_IDX_BB                       0x5     /* BlackBoard, from the TSP GPL sampling framework */
+#define CN_DST_IDX                      0x6
+#define CN_DST_VAL                      0x1
 
-#define CN_NETLINK_USERS                6
+#define CN_NETLINK_USERS                7
 
 /*
  * Maximum connector's message size.
diff --git a/include/linux/dst.h b/include/linux/dst.h
new file mode 100644
index 000000000000..e26fed84b1aa
--- /dev/null
+++ b/include/linux/dst.h
@@ -0,0 +1,587 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
+ * All rights reserved.
+ *
+ * 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.
+ */
+
+#ifndef __DST_H
+#define __DST_H
+
+#include <linux/types.h>
+#include <linux/connector.h>
+
+#define DST_NAMELEN             32
+#define DST_NAME                "dst"
+
+enum {
+        /* Remove node with given id from storage */
+        DST_DEL_NODE    = 0,
+        /* Add remote node with given id to the storage */
+        DST_ADD_REMOTE,
+        /* Add local node with given id to the storage to be exported and used by remote peers */
+        DST_ADD_EXPORT,
+        /* Crypto initialization command (hash/cipher used to protect the connection) */
+        DST_CRYPTO,
+        /* Security attributes for given connection (permissions for example) */
+        DST_SECURITY,
+        /* Register given node in the block layer subsystem */
+        DST_START,
+        DST_CMD_MAX
+};
+
+struct dst_ctl
+{
+        /* Storage name */
+        char                    name[DST_NAMELEN];
+        /* Command flags */
+        __u32                   flags;
+        /* Command itself (see above) */
+        __u32                   cmd;
+        /* Maximum number of pages per single request in this device */
+        __u32                   max_pages;
+        /* Stale/error transaction scanning timeout in milliseconds */
+        __u32                   trans_scan_timeout;
+        /* Maximum number of retry sends before completing transaction as broken */
+        __u32                   trans_max_retries;
+        /* Storage size */
+        __u64                   size;
+};
+
+/* Reply command carries completion status */
+struct dst_ctl_ack
+{
+        struct cn_msg           msg;
+        int                     error;
+        int                     unused[3];
+};
+
+/*
+ * Unfortunaltely socket address structure is not exported to userspace
+ * and is redefined there.
+ */
+#define SADDR_MAX_DATA  128
+
+struct saddr {
+        /* address family, AF_xxx       */
+        unsigned short          sa_family;
+        /* 14 bytes of protocol address */
+        char                    sa_data[SADDR_MAX_DATA];
+        /* Number of bytes used in sa_data */
+        unsigned short          sa_data_len;
+};
+
+/* Address structure */
+struct dst_network_ctl
+{
+        /* Socket type: datagram, stream...*/
+        unsigned int            type;
+        /* Let me guess, is it a Jupiter diameter? */
+        unsigned int            proto;
+        /* Peer's address */
+        struct saddr            addr;
+};
+
+struct dst_crypto_ctl
+{
+        /* Cipher and hash names */
+        char                    cipher_algo[DST_NAMELEN];
+        char                    hash_algo[DST_NAMELEN];
+
+        /* Key sizes. Can be zero for digest for example */
+        unsigned int            cipher_keysize, hash_keysize;
+        /* Alignment. Calculated by the DST itself. */
+        unsigned int            crypto_attached_size;
+        /* Number of threads to perform crypto operations */
+        int                     thread_num;
+};
+
+/* Export security attributes have this bits checked in when client connects */
+#define DST_PERM_READ           (1<<0)
+#define DST_PERM_WRITE          (1<<1)
+
+/*
+ * Right now it is simple model, where each remote address
+ * is assigned to set of permissions it is allowed to perform.
+ * In real world block device does not know anything but
+ * reading and writing, so it should be more than enough.
+ */
+struct dst_secure_user
+{
+        unsigned int            permissions;
+        struct saddr            addr;
+};
+
+/*
+ * Export control command: device to export and network address to accept
+ * clients to work with given device
+ */
+struct dst_export_ctl
+{
+        char                    device[DST_NAMELEN];
+        struct dst_network_ctl  ctl;
+};
+
+enum {
+        DST_CFG = 1,            /* Request remote configuration */
+        DST_IO,                 /* IO command */
+        DST_IO_RESPONSE,        /* IO response */
+        DST_PING,               /* Keepalive message */
+        DST_NCMD_MAX,
+};
+
+struct dst_cmd
+{
+        /* Network command itself, see above */
+        __u32                   cmd;
+        /*
+         * Size of the attached data
+         * (in most cases, for READ command it means how many bytes were requested)
+         */
+        __u32                   size;
+        /* Crypto size: number of attached bytes with digest/hmac */
+        __u32                   csize;
+        /* Here we can carry secret data */
+        __u32                   reserved;
+        /* Read/write bits, see how they are encoded in bio structure */
+        __u64                   rw;
+        /* BIO flags */
+        __u64                   flags;
+        /* Unique command id (like transaction ID) */
+        __u64                   id;
+        /* Sector to start IO from */
+        __u64                   sector;
+        /* Hash data is placed after this header */
+        __u8                    hash[0];
+};
+
+/*
+ * Convert command to/from network byte order.
+ * We do not use hton*() functions, since there is
+ * no 64-bit implementation.
+ */
+static inline void dst_convert_cmd(struct dst_cmd *c)
+{
+        c->cmd = __cpu_to_be32(c->cmd);
+        c->csize = __cpu_to_be32(c->csize);
+        c->size = __cpu_to_be32(c->size);
+        c->sector = __cpu_to_be64(c->sector);
+        c->id = __cpu_to_be64(c->id);
+        c->flags = __cpu_to_be64(c->flags);
+        c->rw = __cpu_to_be64(c->rw);
+}
+
+/* Transaction id */
+typedef __u64 dst_gen_t;
+
+#ifdef __KERNEL__
+
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/device.h>
+#include <linux/mempool.h>
+#include <linux/net.h>
+#include <linux/poll.h>
+#include <linux/rbtree.h>
+
+#ifdef CONFIG_DST_DEBUG
+#define dprintk(f, a...) printk(KERN_NOTICE f, ##a)
+#else
+static inline void __attribute__ ((format (printf, 1, 2)))
+        dprintk(const char *fmt, ...) {}
+#endif
+
+struct dst_node;
+
+struct dst_trans
+{
+        /* DST node we are working with */
+        struct dst_node         *n;
+
+        /* Entry inside transaction tree */
+        struct rb_node          trans_entry;
+
+        /* Merlin kills this transaction when this memory cell equals zero */
+        atomic_t                refcnt;
+
+        /* How this transaction should be processed by crypto engine */
+        short                   enc;
+        /* How many times this transaction was resent */
+        short                   retries;
+        /* Completion status */
+        int                     error;
+
+        /* When did we send it to the remote peer */
+        long                    send_time;
+
+        /* My name is...
+         * Well, computers does not speak, they have unique id instead */
+        dst_gen_t               gen;
+
+        /* Block IO we are working with */
+        struct bio              *bio;
+
+        /* Network command for above block IO request */
+        struct dst_cmd          cmd;
+};
+
+struct dst_crypto_engine
+{
+        /* What should we do with all block requests */
+        struct crypto_hash      *hash;
+        struct crypto_ablkcipher        *cipher;
+
+        /* Pool of pages used to encrypt data into before sending */
+        int                     page_num;
+        struct page             **pages;
+
+        /* What to do with current request */
+        int                     enc;
+        /* Who we are and where do we go */
+        struct scatterlist      *src, *dst;
+
+        /* Maximum timeout waiting for encryption to be completed */
+        long                    timeout;
+        /* IV is a 64-bit sequential counter */
+        u64                     iv;
+
+        /* Secret data */
+        void                    *private;
+
+        /* Cached temporary data lives here */
+        int                     size;
+        void                    *data;
+};
+
+struct dst_state
+{
+        /* The main state protection */
+        struct mutex            state_lock;
+
+        /* Polling machinery for sockets */
+        wait_queue_t            wait;
+        wait_queue_head_t       *whead;
+        /* Most of events are being waited here */
+        wait_queue_head_t       thread_wait;
+
+        /* Who owns this? */
+        struct dst_node         *node;
+
+        /* Network address for this state */
+        struct dst_network_ctl  ctl;
+
+        /* Permissions to work with: read-only or rw connection */
+        u32                     permissions;
+
+        /* Called when we need to clean private data */
+        void                    (* cleanup)(struct dst_state *st);
+
+        /* Used by the server: BIO completion queues BIOs here */
+        struct list_head        request_list;
+        spinlock_t              request_lock;
+
+        /* Guess what? No, it is not number of planets */
+        atomic_t                refcnt;
+
+        /* This flags is set when connection should be dropped */
+        int                     need_exit;
+
+        /*
+         * Socket to work with. Second pointer is used for
+         * lockless check if socket was changed before performing
+         * next action (like working with cached polling result)
+         */
+        struct socket           *socket, *read_socket;
+
+        /* Cached preallocated data */
+        void                    *data;
+        unsigned int            size;
+
+        /* Currently processed command */
+        struct dst_cmd          cmd;
+};
+
+struct dst_info
+{
+        /* Device size */
+        u64                     size;
+
+        /* Local device name for export devices */
+        char                    local[DST_NAMELEN];
+
+        /* Network setup */
+        struct dst_network_ctl  net;
+
+        /* Sysfs bits use this */
+        struct device           device;
+};
+
+struct dst_node
+{
+        struct list_head        node_entry;
+
+        /* Hi, my name is stored here */
+        char                    name[DST_NAMELEN];
+        /* My cache name is stored here */
+        char                    cache_name[DST_NAMELEN];
+
+        /* Block device attached to given node.
+         * Only valid for exporting nodes */
+        struct block_device     *bdev;
+        /* Network state machine for given peer */
+        struct dst_state        *state;
+
+        /* Block IO machinery */
+        struct request_queue    *queue;
+        struct gendisk          *disk;
+
+        /* Number of threads in processing pool */
+        int                     thread_num;
+        /* Maximum number of pages in single IO */
+        int                     max_pages;
+
+        /* I'm that big in bytes */
+        loff_t                  size;
+
+        /* Exported to userspace node information */
+        struct dst_info         *info;
+
+        /*
+         * Security attribute list.
+         * Used only by exporting node currently.
+         */
+        struct list_head        security_list;
+        struct mutex            security_lock;
+
+        /*
+         * When this unerflows below zero, university collapses.
+         * But this will not happen, since node will be freed,
+         * when reference counter reaches zero.
+         */
+        atomic_t                refcnt;
+
+        /* How precisely should I be started? */
+        int                     (*start)(struct dst_node *);
+
+        /* Crypto capabilities */
+        struct dst_crypto_ctl   crypto;
+        u8                      *hash_key;
+        u8                      *cipher_key;
+
+        /* Pool of processing thread */
+        struct thread_pool      *pool;
+
+        /* Transaction IDs live here */
+        atomic_long_t           gen;
+
+        /*
+         * How frequently and how many times transaction
+         * tree should be scanned to drop stale objects.
+         */
+        long                    trans_scan_timeout;
+        int                     trans_max_retries;
+
+        /* Small gnomes live here */
+        struct rb_root          trans_root;
+        struct mutex            trans_lock;
+
+        /*
+         * Transaction cache/memory pool.
+         * It is big enough to contain not only transaction
+         * itself, but additional crypto data (digest/hmac).
+         */
+        struct kmem_cache       *trans_cache;
+        mempool_t               *trans_pool;
+
+        /* This entity scans transaction tree */
+        struct delayed_work     trans_work;
+
+        wait_queue_head_t       wait;
+};
+
+/* Kernel representation of the security attribute */
+struct dst_secure
+{
+        struct list_head        sec_entry;
+        struct dst_secure_user  sec;
+};
+
+int dst_process_bio(struct dst_node *n, struct bio *bio);
+
+int dst_node_init_connected(struct dst_node *n, struct dst_network_ctl *r);
+int dst_node_init_listened(struct dst_node *n, struct dst_export_ctl *le);
+
+static inline struct dst_state *dst_state_get(struct dst_state *st)
+{
+        BUG_ON(atomic_read(&st->refcnt) == 0);
+        atomic_inc(&st->refcnt);
+        return st;
+}
+
+void dst_state_put(struct dst_state *st);
+
+struct dst_state *dst_state_alloc(struct dst_node *n);
+int dst_state_socket_create(struct dst_state *st);
+void dst_state_socket_release(struct dst_state *st);
+
+void dst_state_exit_connected(struct dst_state *st);
+
+int dst_state_schedule_receiver(struct dst_state *st);
+
+void dst_dump_addr(struct socket *sk, struct sockaddr *sa, char *str);
+
+static inline void dst_state_lock(struct dst_state *st)
+{
+        mutex_lock(&st->state_lock);
+}
+
+static inline void dst_state_unlock(struct dst_state *st)
+{
+        mutex_unlock(&st->state_lock);
+}
+
+void dst_poll_exit(struct dst_state *st);
+int dst_poll_init(struct dst_state *st);
+
+static inline unsigned int dst_state_poll(struct dst_state *st)
+{
+        unsigned int revents = POLLHUP | POLLERR;
+
+        dst_state_lock(st);
+        if (st->socket)
+                revents = st->socket->ops->poll(NULL, st->socket, NULL);
+        dst_state_unlock(st);
+
+        return revents;
+}
+
+static inline int dst_thread_setup(void *private, void *data)
+{
+        return 0;
+}
+
+void dst_node_put(struct dst_node *n);
+
+static inline struct dst_node *dst_node_get(struct dst_node *n)
+{
+        atomic_inc(&n->refcnt);
+        return n;
+}
+
+int dst_data_recv(struct dst_state *st, void *data, unsigned int size);
+int dst_recv_cdata(struct dst_state *st, void *cdata);
+int dst_data_send_header(struct socket *sock,
+                void *data, unsigned int size, int more);
+
+int dst_send_bio(struct dst_state *st, struct dst_cmd *cmd, struct bio *bio);
+
+int dst_process_io(struct dst_state *st);
+int dst_export_crypto(struct dst_node *n, struct bio *bio);
+int dst_export_send_bio(struct bio *bio);
+int dst_start_export(struct dst_node *n);
+
+int __init dst_export_init(void);
+void dst_export_exit(void);
+
+/* Private structure for export block IO requests */
+struct dst_export_priv
+{
+        struct list_head                request_entry;
+        struct dst_state                *state;
+        struct bio                      *bio;
+        struct dst_cmd                  cmd;
+};
+
+static inline void dst_trans_get(struct dst_trans *t)
+{
+        atomic_inc(&t->refcnt);
+}
+
+struct dst_trans *dst_trans_search(struct dst_node *node, dst_gen_t gen);
+int dst_trans_remove(struct dst_trans *t);
+int dst_trans_remove_nolock(struct dst_trans *t);
+void dst_trans_put(struct dst_trans *t);
+
+/*
+ * Convert bio into network command.
+ */
+static inline void dst_bio_to_cmd(struct bio *bio, struct dst_cmd *cmd,
+                u32 command, u64 id)
+{
+        cmd->cmd = command;
+        cmd->flags = (bio->bi_flags << BIO_POOL_BITS) >> BIO_POOL_BITS;
+        cmd->rw = bio->bi_rw;
+        cmd->size = bio->bi_size;
+        cmd->csize = 0;
+        cmd->id = id;
+        cmd->sector = bio->bi_sector;
+};
+
+int dst_trans_send(struct dst_trans *t);
+int dst_trans_crypto(struct dst_trans *t);
+
+int dst_node_crypto_init(struct dst_node *n, struct dst_crypto_ctl *ctl);
+void dst_node_crypto_exit(struct dst_node *n);
+
+static inline int dst_need_crypto(struct dst_node *n)
+{
+        struct dst_crypto_ctl *c = &n->crypto;
+        /*
+         * Logical OR is appropriate here, but boolean one produces
+         * more optimal code, so it is used instead.
+         */
+        return (c->hash_algo[0] | c->cipher_algo[0]);
+}
+
+int dst_node_trans_init(struct dst_node *n, unsigned int size);
+void dst_node_trans_exit(struct dst_node *n);
+
+/*
+ * Pool of threads.
+ * Ready list contains threads currently free to be used,
+ * active one contains threads with some work scheduled for them.
+ * Caller can wait in given queue when thread is ready.
+ */
+struct thread_pool
+{
+        int                     thread_num;
+        struct mutex            thread_lock;
+        struct list_head        ready_list, active_list;
+
+        wait_queue_head_t       wait;
+};
+
+void thread_pool_del_worker(struct thread_pool *p);
+void thread_pool_del_worker_id(struct thread_pool *p, unsigned int id);
+int thread_pool_add_worker(struct thread_pool *p,
+                char *name,
+                unsigned int id,
+                void *(* init)(void *data),
+                void (* cleanup)(void *data),
+                void *data);
+
+void thread_pool_destroy(struct thread_pool *p);
+struct thread_pool *thread_pool_create(int num, char *name,
+                void *(* init)(void *data),
+                void (* cleanup)(void *data),
+                void *data);
+
+int thread_pool_schedule(struct thread_pool *p,
+                int (* setup)(void *stored_private, void *setup_data),
+                int (* action)(void *stored_private, void *setup_data),
+                void *setup_data, long timeout);
+int thread_pool_schedule_private(struct thread_pool *p,
+                int (* setup)(void *private, void *data),
+                int (* action)(void *private, void *data),
+                void *data, long timeout, void *id);
+
+#endif /* __KERNEL__ */
+#endif /* __DST_H */