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-rw-r--r--nbd/client.c498
1 files changed, 269 insertions, 229 deletions
diff --git a/nbd/client.c b/nbd/client.c
index f6db8369b3..7db4301d29 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -1,4 +1,5 @@
/*
+ * Copyright (C) 2016 Red Hat, Inc.
* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
*
* Network Block Device Client Side
@@ -22,23 +23,34 @@
static int nbd_errno_to_system_errno(int err)
{
+ int ret;
switch (err) {
case NBD_SUCCESS:
- return 0;
+ ret = 0;
+ break;
case NBD_EPERM:
- return EPERM;
+ ret = EPERM;
+ break;
case NBD_EIO:
- return EIO;
+ ret = EIO;
+ break;
case NBD_ENOMEM:
- return ENOMEM;
+ ret = ENOMEM;
+ break;
case NBD_ENOSPC:
- return ENOSPC;
+ ret = ENOSPC;
+ break;
+ case NBD_ESHUTDOWN:
+ ret = ESHUTDOWN;
+ break;
default:
TRACE("Squashing unexpected error %d to EINVAL", err);
/* fallthrough */
case NBD_EINVAL:
- return EINVAL;
+ ret = EINVAL;
+ break;
}
+ return ret;
}
/* Definitions for opaque data types */
@@ -74,64 +86,180 @@ static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
*/
+/* Discard length bytes from channel. Return -errno on failure, or
+ * the amount of bytes consumed. */
+static ssize_t drop_sync(QIOChannel *ioc, size_t size)
+{
+ ssize_t ret, dropped = size;
+ char small[1024];
+ char *buffer;
+
+ buffer = sizeof(small) < size ? small : g_malloc(MIN(65536, size));
+ while (size > 0) {
+ ret = read_sync(ioc, buffer, MIN(65536, size));
+ if (ret < 0) {
+ goto cleanup;
+ }
+ assert(ret <= size);
+ size -= ret;
+ }
+ ret = dropped;
+
+ cleanup:
+ if (buffer != small) {
+ g_free(buffer);
+ }
+ return ret;
+}
+
+/* Send an option request.
+ *
+ * The request is for option @opt, with @data containing @len bytes of
+ * additional payload for the request (@len may be -1 to treat @data as
+ * a C string; and @data may be NULL if @len is 0).
+ * Return 0 if successful, -1 with errp set if it is impossible to
+ * continue. */
+static int nbd_send_option_request(QIOChannel *ioc, uint32_t opt,
+ uint32_t len, const char *data,
+ Error **errp)
+{
+ nbd_option req;
+ QEMU_BUILD_BUG_ON(sizeof(req) != 16);
+
+ if (len == -1) {
+ req.length = len = strlen(data);
+ }
+ TRACE("Sending option request %" PRIu32", len %" PRIu32, opt, len);
-/* If type represents success, return 1 without further action.
- * If type represents an error reply, consume the rest of the packet on ioc.
- * Then return 0 for unsupported (so the client can fall back to
- * other approaches), or -1 with errp set for other errors.
+ stq_be_p(&req.magic, NBD_OPTS_MAGIC);
+ stl_be_p(&req.option, opt);
+ stl_be_p(&req.length, len);
+
+ if (write_sync(ioc, &req, sizeof(req)) != sizeof(req)) {
+ error_setg(errp, "Failed to send option request header");
+ return -1;
+ }
+
+ if (len && write_sync(ioc, (char *) data, len) != len) {
+ error_setg(errp, "Failed to send option request data");
+ return -1;
+ }
+
+ return 0;
+}
+
+/* Send NBD_OPT_ABORT as a courtesy to let the server know that we are
+ * not going to attempt further negotiation. */
+static void nbd_send_opt_abort(QIOChannel *ioc)
+{
+ /* Technically, a compliant server is supposed to reply to us; but
+ * older servers disconnected instead. At any rate, we're allowed
+ * to disconnect without waiting for the server reply, so we don't
+ * even care if the request makes it to the server, let alone
+ * waiting around for whether the server replies. */
+ nbd_send_option_request(ioc, NBD_OPT_ABORT, 0, NULL, NULL);
+}
+
+
+/* Receive the header of an option reply, which should match the given
+ * opt. Read through the length field, but NOT the length bytes of
+ * payload. Return 0 if successful, -1 with errp set if it is
+ * impossible to continue. */
+static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt,
+ nbd_opt_reply *reply, Error **errp)
+{
+ QEMU_BUILD_BUG_ON(sizeof(*reply) != 20);
+ if (read_sync(ioc, reply, sizeof(*reply)) != sizeof(*reply)) {
+ error_setg(errp, "failed to read option reply");
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+ be64_to_cpus(&reply->magic);
+ be32_to_cpus(&reply->option);
+ be32_to_cpus(&reply->type);
+ be32_to_cpus(&reply->length);
+
+ TRACE("Received option reply %" PRIx32", type %" PRIx32", len %" PRIu32,
+ reply->option, reply->type, reply->length);
+
+ if (reply->magic != NBD_REP_MAGIC) {
+ error_setg(errp, "Unexpected option reply magic");
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+ if (reply->option != opt) {
+ error_setg(errp, "Unexpected option type %x expected %x",
+ reply->option, opt);
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+ return 0;
+}
+
+/* If reply represents success, return 1 without further action.
+ * If reply represents an error, consume the optional payload of
+ * the packet on ioc. Then return 0 for unsupported (so the client
+ * can fall back to other approaches), or -1 with errp set for other
+ * errors.
*/
-static int nbd_handle_reply_err(QIOChannel *ioc, uint32_t opt, uint32_t type,
+static int nbd_handle_reply_err(QIOChannel *ioc, nbd_opt_reply *reply,
Error **errp)
{
- uint32_t len;
char *msg = NULL;
int result = -1;
- if (!(type & (1 << 31))) {
+ if (!(reply->type & (1 << 31))) {
return 1;
}
- if (read_sync(ioc, &len, sizeof(len)) != sizeof(len)) {
- error_setg(errp, "failed to read option length");
- return -1;
- }
- len = be32_to_cpu(len);
- if (len) {
- if (len > NBD_MAX_BUFFER_SIZE) {
+ if (reply->length) {
+ if (reply->length > NBD_MAX_BUFFER_SIZE) {
error_setg(errp, "server's error message is too long");
goto cleanup;
}
- msg = g_malloc(len + 1);
- if (read_sync(ioc, msg, len) != len) {
+ msg = g_malloc(reply->length + 1);
+ if (read_sync(ioc, msg, reply->length) != reply->length) {
error_setg(errp, "failed to read option error message");
goto cleanup;
}
- msg[len] = '\0';
+ msg[reply->length] = '\0';
}
- switch (type) {
+ switch (reply->type) {
case NBD_REP_ERR_UNSUP:
TRACE("server doesn't understand request %" PRIx32
- ", attempting fallback", opt);
+ ", attempting fallback", reply->option);
result = 0;
goto cleanup;
case NBD_REP_ERR_POLICY:
- error_setg(errp, "Denied by server for option %" PRIx32, opt);
+ error_setg(errp, "Denied by server for option %" PRIx32,
+ reply->option);
break;
case NBD_REP_ERR_INVALID:
- error_setg(errp, "Invalid data length for option %" PRIx32, opt);
+ error_setg(errp, "Invalid data length for option %" PRIx32,
+ reply->option);
+ break;
+
+ case NBD_REP_ERR_PLATFORM:
+ error_setg(errp, "Server lacks support for option %" PRIx32,
+ reply->option);
break;
case NBD_REP_ERR_TLS_REQD:
error_setg(errp, "TLS negotiation required before option %" PRIx32,
- opt);
+ reply->option);
+ break;
+
+ case NBD_REP_ERR_SHUTDOWN:
+ error_setg(errp, "Server shutting down before option %" PRIx32,
+ reply->option);
break;
default:
error_setg(errp, "Unknown error code when asking for option %" PRIx32,
- opt);
+ reply->option);
break;
}
@@ -141,244 +269,160 @@ static int nbd_handle_reply_err(QIOChannel *ioc, uint32_t opt, uint32_t type,
cleanup:
g_free(msg);
+ if (result < 0) {
+ nbd_send_opt_abort(ioc);
+ }
return result;
}
-static int nbd_receive_list(QIOChannel *ioc, char **name, Error **errp)
+/* Process another portion of the NBD_OPT_LIST reply. Set *@match if
+ * the current reply matches @want or if the server does not support
+ * NBD_OPT_LIST, otherwise leave @match alone. Return 0 if iteration
+ * is complete, positive if more replies are expected, or negative
+ * with @errp set if an unrecoverable error occurred. */
+static int nbd_receive_list(QIOChannel *ioc, const char *want, bool *match,
+ Error **errp)
{
- uint64_t magic;
- uint32_t opt;
- uint32_t type;
+ nbd_opt_reply reply;
uint32_t len;
uint32_t namelen;
+ char name[NBD_MAX_NAME_SIZE + 1];
int error;
- *name = NULL;
- if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
- error_setg(errp, "failed to read list option magic");
+ if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) {
return -1;
}
- magic = be64_to_cpu(magic);
- if (magic != NBD_REP_MAGIC) {
- error_setg(errp, "Unexpected option list magic");
- return -1;
- }
- if (read_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
- error_setg(errp, "failed to read list option");
- return -1;
+ error = nbd_handle_reply_err(ioc, &reply, errp);
+ if (error <= 0) {
+ /* The server did not support NBD_OPT_LIST, so set *match on
+ * the assumption that any name will be accepted. */
+ *match = true;
+ return error;
}
- opt = be32_to_cpu(opt);
- if (opt != NBD_OPT_LIST) {
- error_setg(errp, "Unexpected option type %" PRIx32 " expected %x",
- opt, NBD_OPT_LIST);
+ len = reply.length;
+
+ if (reply.type == NBD_REP_ACK) {
+ if (len != 0) {
+ error_setg(errp, "length too long for option end");
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+ return 0;
+ } else if (reply.type != NBD_REP_SERVER) {
+ error_setg(errp, "Unexpected reply type %" PRIx32 " expected %x",
+ reply.type, NBD_REP_SERVER);
+ nbd_send_opt_abort(ioc);
return -1;
}
- if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) {
- error_setg(errp, "failed to read list option type");
+ if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) {
+ error_setg(errp, "incorrect option length %" PRIu32, len);
+ nbd_send_opt_abort(ioc);
return -1;
}
- type = be32_to_cpu(type);
- error = nbd_handle_reply_err(ioc, opt, type, errp);
- if (error <= 0) {
- return error;
+ if (read_sync(ioc, &namelen, sizeof(namelen)) != sizeof(namelen)) {
+ error_setg(errp, "failed to read option name length");
+ nbd_send_opt_abort(ioc);
+ return -1;
}
-
- if (read_sync(ioc, &len, sizeof(len)) != sizeof(len)) {
- error_setg(errp, "failed to read option length");
+ namelen = be32_to_cpu(namelen);
+ len -= sizeof(namelen);
+ if (len < namelen) {
+ error_setg(errp, "incorrect option name length");
+ nbd_send_opt_abort(ioc);
return -1;
}
- len = be32_to_cpu(len);
-
- if (type == NBD_REP_ACK) {
- if (len != 0) {
- error_setg(errp, "length too long for option end");
- return -1;
- }
- } else if (type == NBD_REP_SERVER) {
- if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) {
- error_setg(errp, "incorrect option length");
- return -1;
- }
- if (read_sync(ioc, &namelen, sizeof(namelen)) != sizeof(namelen)) {
- error_setg(errp, "failed to read option name length");
- return -1;
- }
- namelen = be32_to_cpu(namelen);
- len -= sizeof(namelen);
- if (len < namelen) {
- error_setg(errp, "incorrect option name length");
- return -1;
- }
- if (namelen > NBD_MAX_NAME_SIZE) {
- error_setg(errp, "export name length too long %" PRIu32, namelen);
+ if (namelen != strlen(want)) {
+ if (drop_sync(ioc, len) != len) {
+ error_setg(errp, "failed to skip export name with wrong length");
+ nbd_send_opt_abort(ioc);
return -1;
}
+ return 1;
+ }
- *name = g_new0(char, namelen + 1);
- if (read_sync(ioc, *name, namelen) != namelen) {
- error_setg(errp, "failed to read export name");
- g_free(*name);
- *name = NULL;
- return -1;
- }
- (*name)[namelen] = '\0';
- len -= namelen;
- if (len) {
- char *buf = g_malloc(len + 1);
- if (read_sync(ioc, buf, len) != len) {
- error_setg(errp, "failed to read export description");
- g_free(*name);
- g_free(buf);
- *name = NULL;
- return -1;
- }
- buf[len] = '\0';
- TRACE("Ignoring export description: %s", buf);
- g_free(buf);
- }
- } else {
- error_setg(errp, "Unexpected reply type %" PRIx32 " expected %x",
- type, NBD_REP_SERVER);
+ assert(namelen < sizeof(name));
+ if (read_sync(ioc, name, namelen) != namelen) {
+ error_setg(errp, "failed to read export name");
+ nbd_send_opt_abort(ioc);
return -1;
}
+ name[namelen] = '\0';
+ len -= namelen;
+ if (drop_sync(ioc, len) != len) {
+ error_setg(errp, "failed to read export description");
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+ if (!strcmp(name, want)) {
+ *match = true;
+ }
return 1;
}
+/* Return -1 on failure, 0 if wantname is an available export. */
static int nbd_receive_query_exports(QIOChannel *ioc,
const char *wantname,
Error **errp)
{
- uint64_t magic = cpu_to_be64(NBD_OPTS_MAGIC);
- uint32_t opt = cpu_to_be32(NBD_OPT_LIST);
- uint32_t length = 0;
bool foundExport = false;
- TRACE("Querying export list");
- if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
- error_setg(errp, "Failed to send list option magic");
- return -1;
- }
-
- if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
- error_setg(errp, "Failed to send list option number");
- return -1;
- }
-
- if (write_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
- error_setg(errp, "Failed to send list option length");
+ TRACE("Querying export list for '%s'", wantname);
+ if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) {
return -1;
}
TRACE("Reading available export names");
while (1) {
- char *name = NULL;
- int ret = nbd_receive_list(ioc, &name, errp);
+ int ret = nbd_receive_list(ioc, wantname, &foundExport, errp);
if (ret < 0) {
- g_free(name);
- name = NULL;
+ /* Server gave unexpected reply */
return -1;
+ } else if (ret == 0) {
+ /* Done iterating. */
+ if (!foundExport) {
+ error_setg(errp, "No export with name '%s' available",
+ wantname);
+ nbd_send_opt_abort(ioc);
+ return -1;
+ }
+ TRACE("Found desired export name '%s'", wantname);
+ return 0;
}
- if (ret == 0) {
- /* Server doesn't support export listing, so
- * we will just assume an export with our
- * wanted name exists */
- foundExport = true;
- break;
- }
- if (name == NULL) {
- TRACE("End of export name list");
- break;
- }
- if (g_str_equal(name, wantname)) {
- foundExport = true;
- TRACE("Found desired export name '%s'", name);
- } else {
- TRACE("Ignored export name '%s'", name);
- }
- g_free(name);
- }
-
- if (!foundExport) {
- error_setg(errp, "No export with name '%s' available", wantname);
- return -1;
}
-
- return 0;
}
static QIOChannel *nbd_receive_starttls(QIOChannel *ioc,
QCryptoTLSCreds *tlscreds,
const char *hostname, Error **errp)
{
- uint64_t magic = cpu_to_be64(NBD_OPTS_MAGIC);
- uint32_t opt = cpu_to_be32(NBD_OPT_STARTTLS);
- uint32_t length = 0;
- uint32_t type;
+ nbd_opt_reply reply;
QIOChannelTLS *tioc;
struct NBDTLSHandshakeData data = { 0 };
TRACE("Requesting TLS from server");
- if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
- error_setg(errp, "Failed to send option magic");
- return NULL;
- }
-
- if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
- error_setg(errp, "Failed to send option number");
- return NULL;
- }
-
- if (write_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
- error_setg(errp, "Failed to send option length");
- return NULL;
- }
-
- TRACE("Getting TLS reply from server1");
- if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
- error_setg(errp, "failed to read option magic");
- return NULL;
- }
- magic = be64_to_cpu(magic);
- if (magic != NBD_REP_MAGIC) {
- error_setg(errp, "Unexpected option magic");
- return NULL;
- }
- TRACE("Getting TLS reply from server2");
- if (read_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
- error_setg(errp, "failed to read option");
- return NULL;
- }
- opt = be32_to_cpu(opt);
- if (opt != NBD_OPT_STARTTLS) {
- error_setg(errp, "Unexpected option type %" PRIx32 " expected %x",
- opt, NBD_OPT_STARTTLS);
+ if (nbd_send_option_request(ioc, NBD_OPT_STARTTLS, 0, NULL, errp) < 0) {
return NULL;
}
TRACE("Getting TLS reply from server");
- if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) {
- error_setg(errp, "failed to read option type");
+ if (nbd_receive_option_reply(ioc, NBD_OPT_STARTTLS, &reply, errp) < 0) {
return NULL;
}
- type = be32_to_cpu(type);
- if (type != NBD_REP_ACK) {
+
+ if (reply.type != NBD_REP_ACK) {
error_setg(errp, "Server rejected request to start TLS %" PRIx32,
- type);
+ reply.type);
+ nbd_send_opt_abort(ioc);
return NULL;
}
- TRACE("Getting TLS reply from server");
- if (read_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
- error_setg(errp, "failed to read option length");
- return NULL;
- }
- length = be32_to_cpu(length);
- if (length != 0) {
+ if (reply.length != 0) {
error_setg(errp, "Start TLS response was not zero %" PRIu32,
- length);
+ reply.length);
+ nbd_send_opt_abort(ioc);
return NULL;
}
@@ -417,6 +461,7 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags,
char buf[256];
uint64_t magic, s;
int rc;
+ bool zeroes = true;
TRACE("Receiving negotiation tlscreds=%p hostname=%s.",
tlscreds, hostname ? hostname : "<null>");
@@ -466,8 +511,6 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags,
if (magic == NBD_OPTS_MAGIC) {
uint32_t clientflags = 0;
- uint32_t opt;
- uint32_t namesize;
uint16_t globalflags;
bool fixedNewStyle = false;
@@ -483,6 +526,11 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags,
TRACE("Server supports fixed new style");
clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE;
}
+ if (globalflags & NBD_FLAG_NO_ZEROES) {
+ zeroes = false;
+ TRACE("Server supports no zeroes");
+ clientflags |= NBD_FLAG_C_NO_ZEROES;
+ }
/* client requested flags */
clientflags = cpu_to_be32(clientflags);
if (write_sync(ioc, &clientflags, sizeof(clientflags)) !=
@@ -517,28 +565,13 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags,
goto fail;
}
}
- /* write the export name */
- magic = cpu_to_be64(magic);
- if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
- error_setg(errp, "Failed to send export name magic");
- goto fail;
- }
- opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
- if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
- error_setg(errp, "Failed to send export name option number");
- goto fail;
- }
- namesize = cpu_to_be32(strlen(name));
- if (write_sync(ioc, &namesize, sizeof(namesize)) !=
- sizeof(namesize)) {
- error_setg(errp, "Failed to send export name length");
- goto fail;
- }
- if (write_sync(ioc, (char *)name, strlen(name)) != strlen(name)) {
- error_setg(errp, "Failed to send export name");
+ /* write the export name request */
+ if (nbd_send_option_request(ioc, NBD_OPT_EXPORT_NAME, -1, name,
+ errp) < 0) {
goto fail;
}
+ /* Read the response */
if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
error_setg(errp, "Failed to read export length");
goto fail;
@@ -585,7 +618,7 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags,
}
TRACE("Size is %" PRIu64 ", export flags %" PRIx16, *size, *flags);
- if (read_sync(ioc, &buf, 124) != 124) {
+ if (zeroes && drop_sync(ioc, 124) != 124) {
error_setg(errp, "Failed to read reserved block");
goto fail;
}
@@ -707,18 +740,20 @@ int nbd_disconnect(int fd)
}
#endif
-ssize_t nbd_send_request(QIOChannel *ioc, struct nbd_request *request)
+ssize_t nbd_send_request(QIOChannel *ioc, NBDRequest *request)
{
uint8_t buf[NBD_REQUEST_SIZE];
ssize_t ret;
TRACE("Sending request to server: "
"{ .from = %" PRIu64", .len = %" PRIu32 ", .handle = %" PRIu64
- ", .type=%" PRIu32 " }",
- request->from, request->len, request->handle, request->type);
+ ", .flags = %" PRIx16 ", .type = %" PRIu16 " }",
+ request->from, request->len, request->handle,
+ request->flags, request->type);
stl_be_p(buf, NBD_REQUEST_MAGIC);
- stl_be_p(buf + 4, request->type);
+ stw_be_p(buf + 4, request->flags);
+ stw_be_p(buf + 6, request->type);
stq_be_p(buf + 8, request->handle);
stq_be_p(buf + 16, request->from);
stl_be_p(buf + 24, request->len);
@@ -735,7 +770,7 @@ ssize_t nbd_send_request(QIOChannel *ioc, struct nbd_request *request)
return 0;
}
-ssize_t nbd_receive_reply(QIOChannel *ioc, struct nbd_reply *reply)
+ssize_t nbd_receive_reply(QIOChannel *ioc, NBDReply *reply)
{
uint8_t buf[NBD_REPLY_SIZE];
uint32_t magic;
@@ -763,6 +798,11 @@ ssize_t nbd_receive_reply(QIOChannel *ioc, struct nbd_reply *reply)
reply->error = nbd_errno_to_system_errno(reply->error);
+ if (reply->error == ESHUTDOWN) {
+ /* This works even on mingw which lacks a native ESHUTDOWN */
+ LOG("server shutting down");
+ return -EINVAL;
+ }
TRACE("Got reply: { magic = 0x%" PRIx32 ", .error = % " PRId32
", handle = %" PRIu64" }",
magic, reply->error, reply->handle);