Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 427 insertions, 0 deletions

diff --git a/include/block/nbd.h b/include/block/nbd.h
new file mode 100644
index 000000000..78d101b77
--- /dev/null
+++ b/include/block/nbd.h
@@ -0,0 +1,427 @@
+/*
+ *  Copyright (C) 2016-2020 Red Hat, Inc.
+ *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
+ *
+ *  Network Block Device
+ *
+ *  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; under version 2 of the License.
+ *
+ *  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.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef NBD_H
+#define NBD_H
+
+#include "block/export.h"
+#include "io/channel-socket.h"
+#include "crypto/tlscreds.h"
+#include "qapi/error.h"
+
+extern const BlockExportDriver blk_exp_nbd;
+
+/* Handshake phase structs - this struct is passed on the wire */
+
+struct NBDOption {
+    uint64_t magic; /* NBD_OPTS_MAGIC */
+    uint32_t option; /* NBD_OPT_* */
+    uint32_t length;
+} QEMU_PACKED;
+typedef struct NBDOption NBDOption;
+
+struct NBDOptionReply {
+    uint64_t magic; /* NBD_REP_MAGIC */
+    uint32_t option; /* NBD_OPT_* */
+    uint32_t type; /* NBD_REP_* */
+    uint32_t length;
+} QEMU_PACKED;
+typedef struct NBDOptionReply NBDOptionReply;
+
+typedef struct NBDOptionReplyMetaContext {
+    NBDOptionReply h; /* h.type = NBD_REP_META_CONTEXT, h.length > 4 */
+    uint32_t context_id;
+    /* metadata context name follows */
+} QEMU_PACKED NBDOptionReplyMetaContext;
+
+/* Transmission phase structs
+ *
+ * Note: these are _NOT_ the same as the network representation of an NBD
+ * request and reply!
+ */
+struct NBDRequest {
+    uint64_t handle;
+    uint64_t from;
+    uint32_t len;
+    uint16_t flags; /* NBD_CMD_FLAG_* */
+    uint16_t type; /* NBD_CMD_* */
+};
+typedef struct NBDRequest NBDRequest;
+
+typedef struct NBDSimpleReply {
+    uint32_t magic;  /* NBD_SIMPLE_REPLY_MAGIC */
+    uint32_t error;
+    uint64_t handle;
+} QEMU_PACKED NBDSimpleReply;
+
+/* Header of all structured replies */
+typedef struct NBDStructuredReplyChunk {
+    uint32_t magic;  /* NBD_STRUCTURED_REPLY_MAGIC */
+    uint16_t flags;  /* combination of NBD_REPLY_FLAG_* */
+    uint16_t type;   /* NBD_REPLY_TYPE_* */
+    uint64_t handle; /* request handle */
+    uint32_t length; /* length of payload */
+} QEMU_PACKED NBDStructuredReplyChunk;
+
+typedef union NBDReply {
+    NBDSimpleReply simple;
+    NBDStructuredReplyChunk structured;
+    struct {
+        /* @magic and @handle fields have the same offset and size both in
+         * simple reply and structured reply chunk, so let them be accessible
+         * without ".simple." or ".structured." specification
+         */
+        uint32_t magic;
+        uint32_t _skip;
+        uint64_t handle;
+    } QEMU_PACKED;
+} NBDReply;
+
+/* Header of chunk for NBD_REPLY_TYPE_OFFSET_DATA */
+typedef struct NBDStructuredReadData {
+    NBDStructuredReplyChunk h; /* h.length >= 9 */
+    uint64_t offset;
+    /* At least one byte of data payload follows, calculated from h.length */
+} QEMU_PACKED NBDStructuredReadData;
+
+/* Complete chunk for NBD_REPLY_TYPE_OFFSET_HOLE */
+typedef struct NBDStructuredReadHole {
+    NBDStructuredReplyChunk h; /* h.length == 12 */
+    uint64_t offset;
+    uint32_t length;
+} QEMU_PACKED NBDStructuredReadHole;
+
+/* Header of all NBD_REPLY_TYPE_ERROR* errors */
+typedef struct NBDStructuredError {
+    NBDStructuredReplyChunk h; /* h.length >= 6 */
+    uint32_t error;
+    uint16_t message_length;
+} QEMU_PACKED NBDStructuredError;
+
+/* Header of NBD_REPLY_TYPE_BLOCK_STATUS */
+typedef struct NBDStructuredMeta {
+    NBDStructuredReplyChunk h; /* h.length >= 12 (at least one extent) */
+    uint32_t context_id;
+    /* extents follows */
+} QEMU_PACKED NBDStructuredMeta;
+
+/* Extent chunk for NBD_REPLY_TYPE_BLOCK_STATUS */
+typedef struct NBDExtent {
+    uint32_t length;
+    uint32_t flags; /* NBD_STATE_* */
+} QEMU_PACKED NBDExtent;
+
+/* Transmission (export) flags: sent from server to client during handshake,
+   but describe what will happen during transmission */
+enum {
+    NBD_FLAG_HAS_FLAGS_BIT          =  0, /* Flags are there */
+    NBD_FLAG_READ_ONLY_BIT          =  1, /* Device is read-only */
+    NBD_FLAG_SEND_FLUSH_BIT         =  2, /* Send FLUSH */
+    NBD_FLAG_SEND_FUA_BIT           =  3, /* Send FUA (Force Unit Access) */
+    NBD_FLAG_ROTATIONAL_BIT         =  4, /* Use elevator algorithm -
+                                             rotational media */
+    NBD_FLAG_SEND_TRIM_BIT          =  5, /* Send TRIM (discard) */
+    NBD_FLAG_SEND_WRITE_ZEROES_BIT  =  6, /* Send WRITE_ZEROES */
+    NBD_FLAG_SEND_DF_BIT            =  7, /* Send DF (Do not Fragment) */
+    NBD_FLAG_CAN_MULTI_CONN_BIT     =  8, /* Multi-client cache consistent */
+    NBD_FLAG_SEND_RESIZE_BIT        =  9, /* Send resize */
+    NBD_FLAG_SEND_CACHE_BIT         = 10, /* Send CACHE (prefetch) */
+    NBD_FLAG_SEND_FAST_ZERO_BIT     = 11, /* FAST_ZERO flag for WRITE_ZEROES */
+};
+
+#define NBD_FLAG_HAS_FLAGS         (1 << NBD_FLAG_HAS_FLAGS_BIT)
+#define NBD_FLAG_READ_ONLY         (1 << NBD_FLAG_READ_ONLY_BIT)
+#define NBD_FLAG_SEND_FLUSH        (1 << NBD_FLAG_SEND_FLUSH_BIT)
+#define NBD_FLAG_SEND_FUA          (1 << NBD_FLAG_SEND_FUA_BIT)
+#define NBD_FLAG_ROTATIONAL        (1 << NBD_FLAG_ROTATIONAL_BIT)
+#define NBD_FLAG_SEND_TRIM         (1 << NBD_FLAG_SEND_TRIM_BIT)
+#define NBD_FLAG_SEND_WRITE_ZEROES (1 << NBD_FLAG_SEND_WRITE_ZEROES_BIT)
+#define NBD_FLAG_SEND_DF           (1 << NBD_FLAG_SEND_DF_BIT)
+#define NBD_FLAG_CAN_MULTI_CONN    (1 << NBD_FLAG_CAN_MULTI_CONN_BIT)
+#define NBD_FLAG_SEND_RESIZE       (1 << NBD_FLAG_SEND_RESIZE_BIT)
+#define NBD_FLAG_SEND_CACHE        (1 << NBD_FLAG_SEND_CACHE_BIT)
+#define NBD_FLAG_SEND_FAST_ZERO    (1 << NBD_FLAG_SEND_FAST_ZERO_BIT)
+
+/* New-style handshake (global) flags, sent from server to client, and
+   control what will happen during handshake phase. */
+#define NBD_FLAG_FIXED_NEWSTYLE   (1 << 0) /* Fixed newstyle protocol. */
+#define NBD_FLAG_NO_ZEROES        (1 << 1) /* End handshake without zeroes. */
+
+/* New-style client flags, sent from client to server to control what happens
+   during handshake phase. */
+#define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */
+#define NBD_FLAG_C_NO_ZEROES      (1 << 1) /* End handshake without zeroes. */
+
+/* Option requests. */
+#define NBD_OPT_EXPORT_NAME       (1)
+#define NBD_OPT_ABORT             (2)
+#define NBD_OPT_LIST              (3)
+/* #define NBD_OPT_PEEK_EXPORT    (4) not in use */
+#define NBD_OPT_STARTTLS          (5)
+#define NBD_OPT_INFO              (6)
+#define NBD_OPT_GO                (7)
+#define NBD_OPT_STRUCTURED_REPLY  (8)
+#define NBD_OPT_LIST_META_CONTEXT (9)
+#define NBD_OPT_SET_META_CONTEXT  (10)
+
+/* Option reply types. */
+#define NBD_REP_ERR(value) ((UINT32_C(1) << 31) | (value))
+
+#define NBD_REP_ACK             (1)    /* Data sending finished. */
+#define NBD_REP_SERVER          (2)    /* Export description. */
+#define NBD_REP_INFO            (3)    /* NBD_OPT_INFO/GO. */
+#define NBD_REP_META_CONTEXT    (4)    /* NBD_OPT_{LIST,SET}_META_CONTEXT */
+
+#define NBD_REP_ERR_UNSUP           NBD_REP_ERR(1)  /* Unknown option */
+#define NBD_REP_ERR_POLICY          NBD_REP_ERR(2)  /* Server denied */
+#define NBD_REP_ERR_INVALID         NBD_REP_ERR(3)  /* Invalid length */
+#define NBD_REP_ERR_PLATFORM        NBD_REP_ERR(4)  /* Not compiled in */
+#define NBD_REP_ERR_TLS_REQD        NBD_REP_ERR(5)  /* TLS required */
+#define NBD_REP_ERR_UNKNOWN         NBD_REP_ERR(6)  /* Export unknown */
+#define NBD_REP_ERR_SHUTDOWN        NBD_REP_ERR(7)  /* Server shutting down */
+#define NBD_REP_ERR_BLOCK_SIZE_REQD NBD_REP_ERR(8)  /* Need INFO_BLOCK_SIZE */
+
+/* Info types, used during NBD_REP_INFO */
+#define NBD_INFO_EXPORT         0
+#define NBD_INFO_NAME           1
+#define NBD_INFO_DESCRIPTION    2
+#define NBD_INFO_BLOCK_SIZE     3
+
+/* Request flags, sent from client to server during transmission phase */
+#define NBD_CMD_FLAG_FUA        (1 << 0) /* 'force unit access' during write */
+#define NBD_CMD_FLAG_NO_HOLE    (1 << 1) /* don't punch hole on zero run */
+#define NBD_CMD_FLAG_DF         (1 << 2) /* don't fragment structured read */
+#define NBD_CMD_FLAG_REQ_ONE    (1 << 3) /* only one extent in BLOCK_STATUS
+                                          * reply chunk */
+#define NBD_CMD_FLAG_FAST_ZERO  (1 << 4) /* fail if WRITE_ZEROES is not fast */
+
+/* Supported request types */
+enum {
+    NBD_CMD_READ = 0,
+    NBD_CMD_WRITE = 1,
+    NBD_CMD_DISC = 2,
+    NBD_CMD_FLUSH = 3,
+    NBD_CMD_TRIM = 4,
+    NBD_CMD_CACHE = 5,
+    NBD_CMD_WRITE_ZEROES = 6,
+    NBD_CMD_BLOCK_STATUS = 7,
+};
+
+#define NBD_DEFAULT_PORT	10809
+
+/* Maximum size of a single READ/WRITE data buffer */
+#define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024)
+
+/*
+ * Maximum size of a protocol string (export name, metadata context name,
+ * etc.).  Use malloc rather than stack allocation for storage of a
+ * string.
+ */
+#define NBD_MAX_STRING_SIZE 4096
+
+/* Two types of reply structures */
+#define NBD_SIMPLE_REPLY_MAGIC      0x67446698
+#define NBD_STRUCTURED_REPLY_MAGIC  0x668e33ef
+
+/* Structured reply flags */
+#define NBD_REPLY_FLAG_DONE          (1 << 0) /* This reply-chunk is last */
+
+/* Structured reply types */
+#define NBD_REPLY_ERR(value)         ((1 << 15) | (value))
+
+#define NBD_REPLY_TYPE_NONE          0
+#define NBD_REPLY_TYPE_OFFSET_DATA   1
+#define NBD_REPLY_TYPE_OFFSET_HOLE   2
+#define NBD_REPLY_TYPE_BLOCK_STATUS  5
+#define NBD_REPLY_TYPE_ERROR         NBD_REPLY_ERR(1)
+#define NBD_REPLY_TYPE_ERROR_OFFSET  NBD_REPLY_ERR(2)
+
+/* Extent flags for base:allocation in NBD_REPLY_TYPE_BLOCK_STATUS */
+#define NBD_STATE_HOLE (1 << 0)
+#define NBD_STATE_ZERO (1 << 1)
+
+/* Extent flags for qemu:dirty-bitmap in NBD_REPLY_TYPE_BLOCK_STATUS */
+#define NBD_STATE_DIRTY (1 << 0)
+
+/* No flags needed for qemu:allocation-depth in NBD_REPLY_TYPE_BLOCK_STATUS */
+
+static inline bool nbd_reply_type_is_error(int type)
+{
+    return type & (1 << 15);
+}
+
+/* NBD errors are based on errno numbers, so there is a 1:1 mapping,
+ * but only a limited set of errno values is specified in the protocol.
+ * Everything else is squashed to EINVAL.
+ */
+#define NBD_SUCCESS    0
+#define NBD_EPERM      1
+#define NBD_EIO        5
+#define NBD_ENOMEM     12
+#define NBD_EINVAL     22
+#define NBD_ENOSPC     28
+#define NBD_EOVERFLOW  75
+#define NBD_ENOTSUP    95
+#define NBD_ESHUTDOWN  108
+
+/* Details collected by NBD_OPT_EXPORT_NAME and NBD_OPT_GO */
+struct NBDExportInfo {
+    /* Set by client before nbd_receive_negotiate() */
+    bool request_sizes;
+    char *x_dirty_bitmap;
+
+    /* Set by client before nbd_receive_negotiate(), or by server results
+     * during nbd_receive_export_list() */
+    char *name; /* must be non-NULL */
+
+    /* In-out fields, set by client before nbd_receive_negotiate() and
+     * updated by server results during nbd_receive_negotiate() */
+    bool structured_reply;
+    bool base_allocation; /* base:allocation context for NBD_CMD_BLOCK_STATUS */
+
+    /* Set by server results during nbd_receive_negotiate() and
+     * nbd_receive_export_list() */
+    uint64_t size;
+    uint16_t flags;
+    uint32_t min_block;
+    uint32_t opt_block;
+    uint32_t max_block;
+
+    uint32_t context_id;
+
+    /* Set by server results during nbd_receive_export_list() */
+    char *description;
+    int n_contexts;
+    char **contexts;
+};
+typedef struct NBDExportInfo NBDExportInfo;
+
+int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
+                          QCryptoTLSCreds *tlscreds,
+                          const char *hostname, QIOChannel **outioc,
+                          NBDExportInfo *info, Error **errp);
+void nbd_free_export_list(NBDExportInfo *info, int count);
+int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
+                            const char *hostname, NBDExportInfo **info,
+                            Error **errp);
+int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info,
+             Error **errp);
+int nbd_send_request(QIOChannel *ioc, NBDRequest *request);
+int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc,
+                                   NBDReply *reply, Error **errp);
+int nbd_client(int fd);
+int nbd_disconnect(int fd);
+int nbd_errno_to_system_errno(int err);
+
+typedef struct NBDExport NBDExport;
+typedef struct NBDClient NBDClient;
+
+void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk);
+
+AioContext *nbd_export_aio_context(NBDExport *exp);
+NBDExport *nbd_export_find(const char *name);
+
+void nbd_client_new(QIOChannelSocket *sioc,
+                    QCryptoTLSCreds *tlscreds,
+                    const char *tlsauthz,
+                    void (*close_fn)(NBDClient *, bool));
+void nbd_client_get(NBDClient *client);
+void nbd_client_put(NBDClient *client);
+
+void nbd_server_is_qemu_nbd(bool value);
+bool nbd_server_is_running(void);
+void nbd_server_start(SocketAddress *addr, const char *tls_creds,
+                      const char *tls_authz, uint32_t max_connections,
+                      Error **errp);
+void nbd_server_start_options(NbdServerOptions *arg, Error **errp);
+
+/* nbd_read
+ * Reads @size bytes from @ioc. Returns 0 on success.
+ */
+static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
+                           const char *desc, Error **errp)
+{
+    ERRP_GUARD();
+    int ret = qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
+
+    if (ret < 0) {
+        if (desc) {
+            error_prepend(errp, "Failed to read %s: ", desc);
+        }
+        return ret;
+    }
+
+    return 0;
+}
+
+#define DEF_NBD_READ_N(bits)                                            \
+static inline int nbd_read##bits(QIOChannel *ioc,                       \
+                                 uint##bits##_t *val,                   \
+                                 const char *desc, Error **errp)        \
+{                                                                       \
+    int ret = nbd_read(ioc, val, sizeof(*val), desc, errp);             \
+    if (ret < 0) {                                                      \
+        return ret;                                                     \
+    }                                                                   \
+    *val = be##bits##_to_cpu(*val);                                     \
+    return 0;                                                           \
+}
+
+DEF_NBD_READ_N(16) /* Defines nbd_read16(). */
+DEF_NBD_READ_N(32) /* Defines nbd_read32(). */
+DEF_NBD_READ_N(64) /* Defines nbd_read64(). */
+
+#undef DEF_NBD_READ_N
+
+static inline bool nbd_reply_is_simple(NBDReply *reply)
+{
+    return reply->magic == NBD_SIMPLE_REPLY_MAGIC;
+}
+
+static inline bool nbd_reply_is_structured(NBDReply *reply)
+{
+    return reply->magic == NBD_STRUCTURED_REPLY_MAGIC;
+}
+
+const char *nbd_reply_type_lookup(uint16_t type);
+const char *nbd_opt_lookup(uint32_t opt);
+const char *nbd_rep_lookup(uint32_t rep);
+const char *nbd_info_lookup(uint16_t info);
+const char *nbd_cmd_lookup(uint16_t info);
+const char *nbd_err_lookup(int err);
+
+/* nbd/client-connection.c */
+typedef struct NBDClientConnection NBDClientConnection;
+
+void nbd_client_connection_enable_retry(NBDClientConnection *conn);
+
+NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr,
+                                               bool do_negotiation,
+                                               const char *export_name,
+                                               const char *x_dirty_bitmap,
+                                               QCryptoTLSCreds *tlscreds);
+void nbd_client_connection_release(NBDClientConnection *conn);
+
+QIOChannel *coroutine_fn
+nbd_co_establish_connection(NBDClientConnection *conn, NBDExportInfo *info,
+                            bool blocking, Error **errp);
+
+void coroutine_fn nbd_co_establish_connection_cancel(NBDClientConnection *conn);
+
+#endif