[Libguestfs] [PATCH nbdkit 2/2] server: Split out NBD protocol code from connections code.
Richard W.M. Jones
rjones at redhat.com
Mon Mar 18 17:02:44 UTC 2019
The code handling the NBD protocol was located in the same file as the
code handling connections, for not really any reason except historical.
This is quite a large code movement which splits out the protocol code
into four new files:
server/protocol-handshake.c initial handshake
server/protocol-handshake-newstyle.c " " (newstyle)
server/protocol-handshake-oldstyle.c " " (oldstyle)
server/protocol.c requests and replies
This also renames functions more logically and gets rid of functions
named with leading underscores.
---
server/internal.h | 22 +
server/connections.c | 1203 +-------------------------
server/protocol-handshake-newstyle.c | 609 +++++++++++++
server/protocol-handshake-oldstyle.c | 94 ++
server/protocol-handshake.c | 130 +++
server/protocol.c | 515 +++++++++++
server/Makefile.am | 4 +
7 files changed, 1389 insertions(+), 1188 deletions(-)
diff --git a/server/internal.h b/server/internal.h
index 8427401..d40a82d 100644
--- a/server/internal.h
+++ b/server/internal.h
@@ -194,6 +194,28 @@ extern int connection_set_handle (struct connection *conn,
__attribute__((__nonnull__ (1 /* not 3 */)));
extern void *connection_get_handle (struct connection *conn, size_t i)
__attribute__((__nonnull__ (1)));
+extern int connection_get_status (struct connection *conn)
+ __attribute__((__nonnull__ (1)));
+extern int connection_set_status (struct connection *conn, int value)
+ __attribute__((__nonnull__ (1)));
+
+/* protocol-handshake.c */
+extern int protocol_handshake (struct connection *conn)
+ __attribute__((__nonnull__ (1)));
+extern int protocol_compute_eflags (struct connection *conn, uint16_t *flags)
+ __attribute__((__nonnull__ (1, 2)));
+
+/* protocol-handshake-oldstyle.c */
+extern int protocol_handshake_oldstyle (struct connection *conn)
+ __attribute__((__nonnull__ (1)));
+
+/* protocol-handshake-newstyle.c */
+extern int protocol_handshake_newstyle (struct connection *conn)
+ __attribute__((__nonnull__ (1)));
+
+/* protocol.c */
+extern int protocol_recv_request_send_reply (struct connection *conn)
+ __attribute__((__nonnull__ (1)));
/* crypto.c */
#define root_tls_certificates_dir sysconfdir "/pki/" PACKAGE_NAME
diff --git a/server/connections.c b/server/connections.c
index 7be282f..4ded28d 100644
--- a/server/connections.c
+++ b/server/connections.c
@@ -39,25 +39,8 @@
#include <inttypes.h>
#include <string.h>
#include <unistd.h>
-#include <errno.h>
-#include <sys/types.h>
-#include <stddef.h>
-#include <assert.h>
-
-#include <pthread.h>
#include "internal.h"
-#include "byte-swapping.h"
-#include "protocol.h"
-
-/* Maximum read or write request that we will handle. */
-#define MAX_REQUEST_SIZE (64 * 1024 * 1024)
-
-/* Maximum number of client options we allow before giving up. */
-#define MAX_NR_OPTIONS 32
-
-/* Maximum length of any option data (bytes). */
-#define MAX_OPTION_LENGTH 4096
/* Default number of parallel requests. */
#define DEFAULT_PARALLEL_REQUESTS 16
@@ -65,8 +48,6 @@
static struct connection *new_connection (int sockin, int sockout,
int nworkers);
static void free_connection (struct connection *conn);
-static int negotiate_handshake (struct connection *conn);
-static int recv_request_send_reply (struct connection *conn);
/* Don't call these raw socket functions directly. Use conn->recv etc. */
static int raw_recv (struct connection *, void *buf, size_t len);
@@ -106,8 +87,8 @@ connection_get_handle (struct connection *conn, size_t i)
return NULL;
}
-static int
-get_status (struct connection *conn)
+int
+connection_get_status (struct connection *conn)
{
int r;
@@ -120,9 +101,10 @@ get_status (struct connection *conn)
}
/* Update the status if the new value is lower than the existing value.
- * For convenience, return the incoming value. */
-static int
-set_status (struct connection *conn, int value)
+ * For convenience, return the incoming value.
+ */
+int
+connection_set_status (struct connection *conn, int value)
{
if (conn->nworkers)
pthread_mutex_lock (&conn->status_lock);
@@ -150,8 +132,8 @@ connection_worker (void *data)
threadlocal_set_name (name);
free (worker);
- while (!quit && get_status (conn) > 0)
- recv_request_send_reply (conn);
+ while (!quit && connection_get_status (conn) > 0)
+ protocol_recv_request_send_reply (conn);
debug ("exiting worker thread %s", threadlocal_get_name ());
free (name);
return NULL;
@@ -199,14 +181,14 @@ _handle_single_connection (int sockin, int sockout)
goto done;
/* Handshake. */
- if (negotiate_handshake (conn) == -1)
+ if (protocol_handshake (conn) == -1)
goto done;
if (!nworkers) {
/* No need for a separate thread. */
debug ("handshake complete, processing requests serially");
- while (!quit && get_status (conn) > 0)
- recv_request_send_reply (conn);
+ while (!quit && connection_get_status (conn) > 0)
+ protocol_recv_request_send_reply (conn);
}
else {
/* Create thread pool to process requests. */
@@ -224,12 +206,12 @@ _handle_single_connection (int sockin, int sockout)
if (!worker) {
perror ("malloc");
- set_status (conn, -1);
+ connection_set_status (conn, -1);
goto wait;
}
if (asprintf (&worker->name, "%s.%d", plugin_name, nworkers) < 0) {
perror ("asprintf");
- set_status (conn, -1);
+ connection_set_status (conn, -1);
free (worker);
goto wait;
}
@@ -239,7 +221,7 @@ _handle_single_connection (int sockin, int sockout)
if (err) {
errno = err;
perror ("pthread_create");
- set_status (conn, -1);
+ connection_set_status (conn, -1);
free (worker);
goto wait;
}
@@ -261,7 +243,7 @@ _handle_single_connection (int sockin, int sockout)
if (r == -1)
goto done;
- ret = get_status (conn);
+ ret = connection_get_status (conn);
done:
free_connection (conn);
return ret;
@@ -335,1161 +317,6 @@ free_connection (struct connection *conn)
free (conn);
}
-static int
-compute_eflags (struct connection *conn, uint16_t *flags)
-{
- uint16_t eflags = NBD_FLAG_HAS_FLAGS;
- int fl;
-
- fl = backend->can_write (backend, conn);
- if (fl == -1)
- return -1;
- if (readonly || !fl) {
- eflags |= NBD_FLAG_READ_ONLY;
- conn->readonly = true;
- }
- if (!conn->readonly) {
- fl = backend->can_zero (backend, conn);
- if (fl == -1)
- return -1;
- if (fl) {
- eflags |= NBD_FLAG_SEND_WRITE_ZEROES;
- conn->can_zero = true;
- }
-
- fl = backend->can_trim (backend, conn);
- if (fl == -1)
- return -1;
- if (fl) {
- eflags |= NBD_FLAG_SEND_TRIM;
- conn->can_trim = true;
- }
-
- fl = backend->can_fua (backend, conn);
- if (fl == -1)
- return -1;
- if (fl) {
- eflags |= NBD_FLAG_SEND_FUA;
- conn->can_fua = true;
- }
- }
-
- fl = backend->can_flush (backend, conn);
- if (fl == -1)
- return -1;
- if (fl) {
- eflags |= NBD_FLAG_SEND_FLUSH;
- conn->can_flush = true;
- }
-
- fl = backend->is_rotational (backend, conn);
- if (fl == -1)
- return -1;
- if (fl) {
- eflags |= NBD_FLAG_ROTATIONAL;
- conn->is_rotational = true;
- }
-
- fl = backend->can_multi_conn (backend, conn);
- if (fl == -1)
- return -1;
- if (fl) {
- eflags |= NBD_FLAG_CAN_MULTI_CONN;
- conn->can_multi_conn = true;
- }
-
- *flags = eflags;
- return 0;
-}
-
-static int
-_negotiate_handshake_oldstyle (struct connection *conn)
-{
- struct old_handshake handshake;
- int64_t r;
- uint64_t exportsize;
- uint16_t gflags, eflags;
-
- /* In --tls=require / FORCEDTLS mode, old style handshakes are
- * rejected because they cannot support TLS.
- */
- if (tls == 2) {
- nbdkit_error ("non-TLS client tried to connect in --tls=require mode");
- return -1;
- }
-
- r = backend->get_size (backend, conn);
- if (r == -1)
- return -1;
- if (r < 0) {
- nbdkit_error (".get_size function returned invalid value "
- "(%" PRIi64 ")", r);
- return -1;
- }
- exportsize = (uint64_t) r;
- conn->exportsize = exportsize;
-
- gflags = 0;
- if (compute_eflags (conn, &eflags) < 0)
- return -1;
-
- debug ("oldstyle negotiation: flags: global 0x%x export 0x%x",
- gflags, eflags);
-
- memset (&handshake, 0, sizeof handshake);
- memcpy (handshake.nbdmagic, "NBDMAGIC", 8);
- handshake.version = htobe64 (OLD_VERSION);
- handshake.exportsize = htobe64 (exportsize);
- handshake.gflags = htobe16 (gflags);
- handshake.eflags = htobe16 (eflags);
-
- if (conn->send (conn, &handshake, sizeof handshake) == -1) {
- nbdkit_error ("write: %m");
- return -1;
- }
-
- return 0;
-}
-
-/* Receive newstyle options. */
-
-static int
-send_newstyle_option_reply (struct connection *conn,
- uint32_t option, uint32_t reply)
-{
- struct fixed_new_option_reply fixed_new_option_reply;
-
- fixed_new_option_reply.magic = htobe64 (NBD_REP_MAGIC);
- fixed_new_option_reply.option = htobe32 (option);
- fixed_new_option_reply.reply = htobe32 (reply);
- fixed_new_option_reply.replylen = htobe32 (0);
-
- if (conn->send (conn,
- &fixed_new_option_reply,
- sizeof fixed_new_option_reply) == -1) {
- nbdkit_error ("write: %m");
- return -1;
- }
-
- return 0;
-}
-
-static int
-send_newstyle_option_reply_exportname (struct connection *conn,
- uint32_t option, uint32_t reply,
- const char *exportname)
-{
- struct fixed_new_option_reply fixed_new_option_reply;
- size_t name_len = strlen (exportname);
- uint32_t len;
-
- fixed_new_option_reply.magic = htobe64 (NBD_REP_MAGIC);
- fixed_new_option_reply.option = htobe32 (option);
- fixed_new_option_reply.reply = htobe32 (reply);
- fixed_new_option_reply.replylen = htobe32 (name_len + sizeof (len));
-
- if (conn->send (conn,
- &fixed_new_option_reply,
- sizeof fixed_new_option_reply) == -1) {
- nbdkit_error ("write: %m");
- return -1;
- }
-
- len = htobe32 (name_len);
- if (conn->send (conn, &len, sizeof len) == -1) {
- nbdkit_error ("write: %m");
- return -1;
- }
- if (conn->send (conn, exportname, name_len) == -1) {
- nbdkit_error ("write: %m");
- return -1;
- }
-
- return 0;
-}
-
-static int
-send_newstyle_option_reply_info_export (struct connection *conn,
- uint32_t option, uint32_t reply,
- uint16_t info)
-{
- struct fixed_new_option_reply fixed_new_option_reply;
- struct fixed_new_option_reply_info_export export;
-
- fixed_new_option_reply.magic = htobe64 (NBD_REP_MAGIC);
- fixed_new_option_reply.option = htobe32 (option);
- fixed_new_option_reply.reply = htobe32 (reply);
- fixed_new_option_reply.replylen = htobe32 (sizeof export);
- export.info = htobe16 (info);
- export.exportsize = htobe64 (conn->exportsize);
- export.eflags = htobe16 (conn->eflags);
-
- if (conn->send (conn,
- &fixed_new_option_reply,
- sizeof fixed_new_option_reply) == -1 ||
- conn->send (conn, &export, sizeof export) == -1) {
- nbdkit_error ("write: %m");
- return -1;
- }
-
- return 0;
-}
-
-/* Sub-function during _negotiate_handshake_newstyle, to uniformly handle
- * a client hanging up on a message boundary.
- */
-static int __attribute__ ((format (printf, 4, 5)))
-conn_recv_full (struct connection *conn, void *buf, size_t len,
- const char *fmt, ...)
-{
- int r = conn->recv (conn, buf, len);
- va_list args;
-
- if (r == -1) {
- va_start (args, fmt);
- nbdkit_verror (fmt, args);
- va_end (args);
- return -1;
- }
- if (r == 0) {
- /* During negotiation, client EOF on message boundary is less
- * severe than failure in the middle of the buffer. */
- debug ("client closed input socket, closing connection");
- return -1;
- }
- return r;
-}
-
-/* Sub-function of _negotiate_handshake_newstyle_options below. It
- * must be called on all non-error paths out of the options for-loop
- * in that function.
- */
-static int
-finish_newstyle_options (struct connection *conn)
-{
- int64_t r;
-
- r = backend->get_size (backend, conn);
- if (r == -1)
- return -1;
- if (r < 0) {
- nbdkit_error (".get_size function returned invalid value "
- "(%" PRIi64 ")", r);
- return -1;
- }
- conn->exportsize = (uint64_t) r;
-
- if (compute_eflags (conn, &conn->eflags) < 0)
- return -1;
-
- debug ("newstyle negotiation: flags: export 0x%x", conn->eflags);
- return 0;
-}
-
-static int
-_negotiate_handshake_newstyle_options (struct connection *conn)
-{
- struct new_option new_option;
- size_t nr_options;
- uint64_t version;
- uint32_t option;
- uint32_t optlen;
- char data[MAX_OPTION_LENGTH+1];
- struct new_handshake_finish handshake_finish;
- const char *optname;
-
- for (nr_options = 0; nr_options < MAX_NR_OPTIONS; ++nr_options) {
- if (conn_recv_full (conn, &new_option, sizeof new_option,
- "reading option: conn->recv: %m") == -1)
- return -1;
-
- version = be64toh (new_option.version);
- if (version != NEW_VERSION) {
- nbdkit_error ("unknown option version %" PRIx64
- ", expecting %" PRIx64,
- version, NEW_VERSION);
- return -1;
- }
-
- /* There is a maximum option length we will accept, regardless
- * of the option type.
- */
- optlen = be32toh (new_option.optlen);
- if (optlen > MAX_OPTION_LENGTH) {
- nbdkit_error ("client option data too long (%" PRIu32 ")", optlen);
- return -1;
- }
-
- option = be32toh (new_option.option);
-
- /* In --tls=require / FORCEDTLS mode the only options allowed
- * before TLS negotiation are NBD_OPT_ABORT and NBD_OPT_STARTTLS.
- */
- if (tls == 2 && !conn->using_tls &&
- !(option == NBD_OPT_ABORT || option == NBD_OPT_STARTTLS)) {
- if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_TLS_REQD))
- return -1;
- continue;
- }
-
- switch (option) {
- case NBD_OPT_EXPORT_NAME:
- if (conn_recv_full (conn, data, optlen,
- "read: %s: %m", name_of_nbd_opt (option)) == -1)
- return -1;
- /* Apart from printing it, ignore the export name. */
- data[optlen] = '\0';
- debug ("newstyle negotiation: %s: "
- "client requested export '%s' (ignored)",
- name_of_nbd_opt (option), data);
-
- /* We have to finish the handshake by sending handshake_finish. */
- if (finish_newstyle_options (conn) == -1)
- return -1;
-
- memset (&handshake_finish, 0, sizeof handshake_finish);
- handshake_finish.exportsize = htobe64 (conn->exportsize);
- handshake_finish.eflags = htobe16 (conn->eflags);
-
- if (conn->send (conn,
- &handshake_finish,
- (conn->cflags & NBD_FLAG_NO_ZEROES)
- ? offsetof (struct new_handshake_finish, zeroes)
- : sizeof handshake_finish) == -1) {
- nbdkit_error ("write: %m");
- return -1;
- }
- break;
-
- case NBD_OPT_ABORT:
- if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
- return -1;
- debug ("client sent %s to abort the connection",
- name_of_nbd_opt (option));
- return -1;
-
- case NBD_OPT_LIST:
- if (optlen != 0) {
- if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
- == -1)
- return -1;
- if (conn_recv_full (conn, data, optlen,
- "read: %s: %m", name_of_nbd_opt (option)) == -1)
- return -1;
- continue;
- }
-
- /* Send back the exportname. */
- debug ("newstyle negotiation: %s: advertising export '%s'",
- name_of_nbd_opt (option), exportname);
- if (send_newstyle_option_reply_exportname (conn, option, NBD_REP_SERVER,
- exportname) == -1)
- return -1;
-
- if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
- return -1;
- break;
-
- case NBD_OPT_STARTTLS:
- if (optlen != 0) {
- if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
- == -1)
- return -1;
- if (conn_recv_full (conn, data, optlen,
- "read: %s: %m", name_of_nbd_opt (option)) == -1)
- return -1;
- continue;
- }
-
- if (tls == 0) { /* --tls=off (NOTLS mode). */
-#ifdef HAVE_GNUTLS
-#define NO_TLS_REPLY NBD_REP_ERR_POLICY
-#else
-#define NO_TLS_REPLY NBD_REP_ERR_UNSUP
-#endif
- if (send_newstyle_option_reply (conn, option, NO_TLS_REPLY) == -1)
- return -1;
- }
- else /* --tls=on or --tls=require */ {
- /* We can't upgrade to TLS twice on the same connection. */
- if (conn->using_tls) {
- if (send_newstyle_option_reply (conn, option,
- NBD_REP_ERR_INVALID) == -1)
- return -1;
- continue;
- }
-
- /* We have to send the (unencrypted) reply before starting
- * the handshake.
- */
- if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
- return -1;
-
- /* Upgrade the connection to TLS. Also performs access control. */
- if (crypto_negotiate_tls (conn, conn->sockin, conn->sockout) == -1)
- return -1;
- conn->using_tls = true;
- debug ("using TLS on this connection");
- }
- break;
-
- case NBD_OPT_INFO:
- case NBD_OPT_GO:
- optname = name_of_nbd_opt (option);
- if (conn_recv_full (conn, data, optlen,
- "read: %s: %m", optname) == -1)
- return -1;
-
- if (optlen < 6) { /* 32 bit export length + 16 bit nr info */
- debug ("newstyle negotiation: %s option length < 6", optname);
-
- if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
- == -1)
- return -1;
- continue;
- }
-
- {
- uint32_t exportnamelen;
- uint16_t nrinfos;
- uint16_t info;
- size_t i;
- CLEANUP_FREE char *requested_exportname = NULL;
-
- /* Validate the name length and number of INFO requests. */
- memcpy (&exportnamelen, &data[0], 4);
- exportnamelen = be32toh (exportnamelen);
- if (exportnamelen > optlen-6 /* NB optlen >= 6, see above */) {
- debug ("newstyle negotiation: %s: export name too long", optname);
- if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
- == -1)
- return -1;
- continue;
- }
- memcpy (&nrinfos, &data[exportnamelen+4], 2);
- nrinfos = be16toh (nrinfos);
- if (optlen != 4 + exportnamelen + 2 + 2*nrinfos) {
- debug ("newstyle negotiation: %s: "
- "number of information requests incorrect", optname);
- if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
- == -1)
- return -1;
- continue;
- }
-
- /* As with NBD_OPT_EXPORT_NAME we print the export name and then
- * ignore it.
- */
- requested_exportname = malloc (exportnamelen+1);
- if (requested_exportname == NULL) {
- nbdkit_error ("malloc: %m");
- return -1;
- }
- memcpy (requested_exportname, &data[4], exportnamelen);
- requested_exportname[exportnamelen] = '\0';
- debug ("newstyle negotiation: %s: "
- "client requested export '%s' (ignored)",
- optname, requested_exportname);
-
- /* The spec is confusing, but it is required that we send back
- * NBD_INFO_EXPORT, even if the client did not request it!
- * qemu client in particular does not request this, but will
- * fail if we don't send it.
- */
- if (finish_newstyle_options (conn) == -1)
- return -1;
-
- if (send_newstyle_option_reply_info_export (conn, option,
- NBD_REP_INFO,
- NBD_INFO_EXPORT) == -1)
- return -1;
-
- /* For now we ignore all other info requests (but we must
- * ignore NBD_INFO_EXPORT if it was requested, because we
- * replied already above). Therefore this loop doesn't do
- * much at the moment.
- */
- for (i = 0; i < nrinfos; ++i) {
- memcpy (&info, &data[4 + exportnamelen + 2 + i*2], 2);
- info = be16toh (info);
- switch (info) {
- case NBD_INFO_EXPORT: /* ignore - reply sent above */ break;
- default:
- debug ("newstyle negotiation: %s: "
- "ignoring NBD_INFO_* request %u (%s)",
- optname, (unsigned) info, name_of_nbd_info (info));
- break;
- }
- }
- }
-
- /* Unlike NBD_OPT_EXPORT_NAME, NBD_OPT_GO sends back an ACK
- * or ERROR packet.
- */
- if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
- return -1;
-
- break;
-
- case NBD_OPT_STRUCTURED_REPLY:
- if (optlen != 0) {
- if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
- == -1)
- return -1;
- if (conn_recv_full (conn, data, optlen,
- "read: %s: %m", name_of_nbd_opt (option)) == -1)
- return -1;
- continue;
- }
-
- debug ("newstyle negotiation: %s: client requested structured replies",
- name_of_nbd_opt (option));
-
- if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
- return -1;
-
- conn->structured_replies = true;
- break;
-
- case NBD_OPT_LIST_META_CONTEXT:
- case NBD_OPT_SET_META_CONTEXT:
- {
- uint32_t opt_index;
- uint32_t exportnamelen;
- uint32_t nr_queries;
- uint32_t querylen;
- const char *what;
-
- optname = name_of_nbd_opt (option);
- if (conn_recv_full (conn, data, optlen, "read: %s: %m", optname) == -1)
- return -1;
-
- if (!conn->structured_replies) {
- if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
- == -1)
- return -1;
- continue;
- }
-
- /* Minimum length of the option payload is:
- * 32 bit export name length followed by empty export name
- * + 32 bit number of queries followed by no queries
- * = 8 bytes.
- */
- what = "optlen < 8";
- if (optlen < 8) {
- opt_meta_invalid_option_len:
- debug ("newstyle negotiation: %s: invalid option length: %s",
- optname, what);
-
- if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
- == -1)
- return -1;
- continue;
- }
-
- /* Discard the export name. */
- memcpy (&exportnamelen, &data[0], 4);
- exportnamelen = be32toh (exportnamelen);
- opt_index = 4 + exportnamelen;
-
- /* Read the number of queries. */
- what = "reading number of queries";
- if (opt_index+4 > optlen)
- goto opt_meta_invalid_option_len;
- memcpy (&nr_queries, &data[opt_index], 4);
- nr_queries = be32toh (nr_queries);
- opt_index += 4;
-
- /* for LIST: nr_queries == 0 means return all meta contexts
- * for SET: nr_queries == 0 means reset all contexts
- */
- if (nr_queries == 0) {
- /* Nothing is supported now. */
- if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
- return -1;
- }
- else {
- /* Read and answer each query. */
- while (nr_queries > 0) {
- what = "reading query string length";
- if (opt_index+4 > optlen)
- goto opt_meta_invalid_option_len;
- memcpy (&querylen, &data[opt_index], 4);
- querylen = be32toh (querylen);
- opt_index += 4;
- what = "reading query string";
- if (opt_index + querylen > optlen)
- goto opt_meta_invalid_option_len;
-
- debug ("newstyle negotiation: %s: %s %.*s",
- optname,
- option == NBD_OPT_LIST_META_CONTEXT ? "query" : "set",
- (int) querylen, &data[opt_index]);
-
- /* Ignore query - nothing is supported. */
-
- opt_index += querylen;
- nr_queries--;
- }
- if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
- return -1;
- }
- }
- break;
-
- default:
- /* Unknown option. */
- if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_UNSUP) == -1)
- return -1;
- if (conn_recv_full (conn, data, optlen,
- "reading unknown option data: conn->recv: %m") == -1)
- return -1;
- }
-
- /* Note, since it's not very clear from the protocol doc, that the
- * client must send NBD_OPT_EXPORT_NAME or NBD_OPT_GO last, and
- * that ends option negotiation.
- */
- if (option == NBD_OPT_EXPORT_NAME || option == NBD_OPT_GO)
- break;
- }
-
- if (nr_options >= MAX_NR_OPTIONS) {
- nbdkit_error ("client exceeded maximum number of options (%d)",
- MAX_NR_OPTIONS);
- return -1;
- }
-
- /* In --tls=require / FORCEDTLS mode, we must have upgraded to TLS
- * by the time we finish option negotiation. If not, give up.
- */
- if (tls == 2 && !conn->using_tls) {
- nbdkit_error ("non-TLS client tried to connect in --tls=require mode");
- return -1;
- }
-
- return 0;
-}
-
-static int
-_negotiate_handshake_newstyle (struct connection *conn)
-{
- struct new_handshake handshake;
- uint16_t gflags;
-
- gflags = NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES;
-
- debug ("newstyle negotiation: flags: global 0x%x", gflags);
-
- memcpy (handshake.nbdmagic, "NBDMAGIC", 8);
- handshake.version = htobe64 (NEW_VERSION);
- handshake.gflags = htobe16 (gflags);
-
- if (conn->send (conn, &handshake, sizeof handshake) == -1) {
- nbdkit_error ("write: %m");
- return -1;
- }
-
- /* Client now sends us its 32 bit flags word ... */
- if (conn_recv_full (conn, &conn->cflags, sizeof conn->cflags,
- "reading initial client flags: conn->recv: %m") == -1)
- return -1;
- conn->cflags = be32toh (conn->cflags);
- /* ... which we check for accuracy. */
- debug ("newstyle negotiation: client flags: 0x%x", conn->cflags);
- if (conn->cflags & ~gflags) {
- nbdkit_error ("client requested unknown flags 0x%x", conn->cflags);
- return -1;
- }
-
- /* Receive newstyle options. */
- if (_negotiate_handshake_newstyle_options (conn) == -1)
- return -1;
-
- return 0;
-}
-
-static int
-negotiate_handshake (struct connection *conn)
-{
- int r;
-
- lock_request (conn);
- if (!newstyle)
- r = _negotiate_handshake_oldstyle (conn);
- else
- r = _negotiate_handshake_newstyle (conn);
- unlock_request (conn);
-
- return r;
-}
-
-static bool
-valid_range (struct connection *conn, uint64_t offset, uint32_t count)
-{
- uint64_t exportsize = conn->exportsize;
-
- return count > 0 && offset <= exportsize && offset + count <= exportsize;
-}
-
-static bool
-validate_request (struct connection *conn,
- uint16_t cmd, uint16_t flags, uint64_t offset, uint32_t count,
- uint32_t *error)
-{
- /* Readonly connection? */
- if (conn->readonly &&
- (cmd == NBD_CMD_WRITE || cmd == NBD_CMD_TRIM ||
- cmd == NBD_CMD_WRITE_ZEROES)) {
- nbdkit_error ("invalid request: %s: write request on readonly connection",
- name_of_nbd_cmd (cmd));
- *error = EROFS;
- return false;
- }
-
- /* Validate cmd, offset, count. */
- switch (cmd) {
- case NBD_CMD_READ:
- case NBD_CMD_WRITE:
- case NBD_CMD_TRIM:
- case NBD_CMD_WRITE_ZEROES:
- if (!valid_range (conn, offset, count)) {
- /* XXX Allow writes to extend the disk? */
- nbdkit_error ("invalid request: %s: offset and count are out of range: "
- "offset=%" PRIu64 " count=%" PRIu32,
- name_of_nbd_cmd (cmd), offset, count);
- *error = (cmd == NBD_CMD_WRITE ||
- cmd == NBD_CMD_WRITE_ZEROES) ? ENOSPC : EINVAL;
- return false;
- }
- break;
-
- case NBD_CMD_FLUSH:
- if (offset != 0 || count != 0) {
- nbdkit_error ("invalid request: %s: expecting offset and count = 0",
- name_of_nbd_cmd (cmd));
- *error = EINVAL;
- return false;
- }
- break;
-
- default:
- nbdkit_error ("invalid request: unknown command (%" PRIu32 ") ignored",
- cmd);
- *error = EINVAL;
- return false;
- }
-
- /* Validate flags */
- if (flags & ~(NBD_CMD_FLAG_FUA | NBD_CMD_FLAG_NO_HOLE)) {
- nbdkit_error ("invalid request: unknown flag (0x%x)", flags);
- *error = EINVAL;
- return false;
- }
- if ((flags & NBD_CMD_FLAG_NO_HOLE) &&
- cmd != NBD_CMD_WRITE_ZEROES) {
- nbdkit_error ("invalid request: NO_HOLE flag needs WRITE_ZEROES request");
- *error = EINVAL;
- return false;
- }
- if (!conn->can_fua && (flags & NBD_CMD_FLAG_FUA)) {
- nbdkit_error ("invalid request: FUA flag not supported");
- *error = EINVAL;
- return false;
- }
-
- /* Refuse over-large read and write requests. */
- if ((cmd == NBD_CMD_WRITE || cmd == NBD_CMD_READ) &&
- count > MAX_REQUEST_SIZE) {
- nbdkit_error ("invalid request: %s: data request is too large (%" PRIu32
- " > %d)",
- name_of_nbd_cmd (cmd), count, MAX_REQUEST_SIZE);
- *error = ENOMEM;
- return false;
- }
-
- /* Flush allowed? */
- if (!conn->can_flush && cmd == NBD_CMD_FLUSH) {
- nbdkit_error ("invalid request: %s: flush operation not supported",
- name_of_nbd_cmd (cmd));
- *error = EINVAL;
- return false;
- }
-
- /* Trim allowed? */
- if (!conn->can_trim && cmd == NBD_CMD_TRIM) {
- nbdkit_error ("invalid request: %s: trim operation not supported",
- name_of_nbd_cmd (cmd));
- *error = EINVAL;
- return false;
- }
-
- /* Zero allowed? */
- if (!conn->can_zero && cmd == NBD_CMD_WRITE_ZEROES) {
- nbdkit_error ("invalid request: %s: write zeroes operation not supported",
- name_of_nbd_cmd (cmd));
- *error = EINVAL;
- return false;
- }
-
- return true; /* Command validates. */
-}
-
-/* This is called with the request lock held to actually execute the
- * request (by calling the plugin). Note that the request fields have
- * been validated already in 'validate_request' so we don't have to
- * check them again. 'buf' is either the data to be written or the
- * data to be returned, and points to a buffer of size 'count' bytes.
- *
- * In all cases, the return value is the system errno value that will
- * later be converted to the nbd error to send back to the client (0
- * for success).
- */
-static uint32_t
-handle_request (struct connection *conn,
- uint16_t cmd, uint16_t flags, uint64_t offset, uint32_t count,
- void *buf)
-{
- uint32_t f = 0;
- bool fua = conn->can_fua && (flags & NBD_CMD_FLAG_FUA);
- int err = 0;
-
- /* Clear the error, so that we know if the plugin calls
- * nbdkit_set_error() or relied on errno. */
- threadlocal_set_error (0);
-
- switch (cmd) {
- case NBD_CMD_READ:
- if (backend->pread (backend, conn, buf, count, offset, 0, &err) == -1)
- return err;
- break;
-
- case NBD_CMD_WRITE:
- if (fua)
- f |= NBDKIT_FLAG_FUA;
- if (backend->pwrite (backend, conn, buf, count, offset, f, &err) == -1)
- return err;
- break;
-
- case NBD_CMD_FLUSH:
- if (backend->flush (backend, conn, 0, &err) == -1)
- return err;
- break;
-
- case NBD_CMD_TRIM:
- if (fua)
- f |= NBDKIT_FLAG_FUA;
- if (backend->trim (backend, conn, count, offset, f, &err) == -1)
- return err;
- break;
-
- case NBD_CMD_WRITE_ZEROES:
- if (!(flags & NBD_CMD_FLAG_NO_HOLE))
- f |= NBDKIT_FLAG_MAY_TRIM;
- if (fua)
- f |= NBDKIT_FLAG_FUA;
- if (backend->zero (backend, conn, count, offset, f, &err) == -1)
- return err;
- break;
-
- default:
- abort ();
- }
-
- return 0;
-}
-
-static int
-skip_over_write_buffer (int sock, size_t count)
-{
- char buf[BUFSIZ];
- ssize_t r;
-
- if (count > MAX_REQUEST_SIZE * 2) {
- nbdkit_error ("write request too large to skip");
- return -1;
- }
-
- while (count > 0) {
- r = read (sock, buf, count > BUFSIZ ? BUFSIZ : count);
- if (r == -1) {
- nbdkit_error ("skipping write buffer: %m");
- return -1;
- }
- if (r == 0) {
- nbdkit_error ("unexpected early EOF");
- errno = EBADMSG;
- return -1;
- }
- count -= r;
- }
- return 0;
-}
-
-/* Convert a system errno to an NBD_E* error code. */
-static int
-nbd_errno (int error)
-{
- switch (error) {
- case 0:
- return NBD_SUCCESS;
- case EROFS:
- case EPERM:
- return NBD_EPERM;
- case EIO:
- return NBD_EIO;
- case ENOMEM:
- return NBD_ENOMEM;
-#ifdef EDQUOT
- case EDQUOT:
-#endif
- case EFBIG:
- case ENOSPC:
- return NBD_ENOSPC;
-#ifdef ESHUTDOWN
- case ESHUTDOWN:
- return NBD_ESHUTDOWN;
-#endif
- case EINVAL:
- default:
- return NBD_EINVAL;
- }
-}
-
-static int
-send_simple_reply (struct connection *conn,
- uint64_t handle, uint16_t cmd,
- const char *buf, uint32_t count,
- uint32_t error)
-{
- ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&conn->write_lock);
- struct simple_reply reply;
- int r;
-
- reply.magic = htobe32 (NBD_SIMPLE_REPLY_MAGIC);
- reply.handle = handle;
- reply.error = htobe32 (nbd_errno (error));
-
- r = conn->send (conn, &reply, sizeof reply);
- if (r == -1) {
- nbdkit_error ("write reply: %s: %m", name_of_nbd_cmd (cmd));
- return set_status (conn, -1);
- }
-
- /* Send the read data buffer. */
- if (cmd == NBD_CMD_READ && !error) {
- r = conn->send (conn, buf, count);
- if (r == -1) {
- nbdkit_error ("write data: %s: %m", name_of_nbd_cmd (cmd));
- return set_status (conn, -1);
- }
- }
-
- return 1; /* command processed ok */
-}
-
-static int
-send_structured_reply_read (struct connection *conn,
- uint64_t handle, uint16_t cmd,
- const char *buf, uint32_t count, uint64_t offset)
-{
- /* Once we are really using structured replies and sending data back
- * in chunks, we'll be able to grab the write lock for each chunk,
- * allowing other threads to interleave replies. As we're not doing
- * that yet we acquire the lock for the whole function.
- */
- ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&conn->write_lock);
- struct structured_reply reply;
- struct structured_reply_offset_data offset_data;
- int r;
-
- assert (cmd == NBD_CMD_READ);
-
- reply.magic = htobe32 (NBD_STRUCTURED_REPLY_MAGIC);
- reply.handle = handle;
- reply.flags = htobe16 (NBD_REPLY_FLAG_DONE);
- reply.type = htobe16 (NBD_REPLY_TYPE_OFFSET_DATA);
- reply.length = htobe32 (count + sizeof offset_data);
-
- r = conn->send (conn, &reply, sizeof reply);
- if (r == -1) {
- nbdkit_error ("write reply: %s: %m", name_of_nbd_cmd (cmd));
- return set_status (conn, -1);
- }
-
- /* Send the offset + read data buffer. */
- offset_data.offset = htobe64 (offset);
- r = conn->send (conn, &offset_data, sizeof offset_data);
- if (r == -1) {
- nbdkit_error ("write data: %s: %m", name_of_nbd_cmd (cmd));
- return set_status (conn, -1);
- }
-
- r = conn->send (conn, buf, count);
- if (r == -1) {
- nbdkit_error ("write data: %s: %m", name_of_nbd_cmd (cmd));
- return set_status (conn, -1);
- }
-
- return 1; /* command processed ok */
-}
-
-static int
-send_structured_reply_error (struct connection *conn,
- uint64_t handle, uint16_t cmd, uint32_t error)
-{
- ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&conn->write_lock);
- struct structured_reply reply;
- struct structured_reply_error error_data;
- int r;
-
- reply.magic = htobe32 (NBD_STRUCTURED_REPLY_MAGIC);
- reply.handle = handle;
- reply.flags = htobe16 (NBD_REPLY_FLAG_DONE);
- reply.type = htobe16 (NBD_REPLY_TYPE_ERROR);
- reply.length = htobe32 (0 /* no human readable error */ + sizeof error_data);
-
- r = conn->send (conn, &reply, sizeof reply);
- if (r == -1) {
- nbdkit_error ("write error reply: %m");
- return set_status (conn, -1);
- }
-
- /* Send the error. */
- error_data.error = htobe32 (error);
- error_data.len = htobe16 (0);
- r = conn->send (conn, &error_data, sizeof error_data);
- if (r == -1) {
- nbdkit_error ("write data: %s: %m", name_of_nbd_cmd (cmd));
- return set_status (conn, -1);
- }
- /* No human readable error message at the moment. */
-
- return 1; /* command processed ok */
-}
-
-static int
-recv_request_send_reply (struct connection *conn)
-{
- int r;
- struct request request;
- uint16_t cmd, flags;
- uint32_t magic, count, error = 0;
- uint64_t offset;
- CLEANUP_FREE char *buf = NULL;
-
- /* Read the request packet. */
- {
- ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&conn->read_lock);
- r = get_status (conn);
- if (r <= 0)
- return r;
- r = conn->recv (conn, &request, sizeof request);
- if (r == -1) {
- nbdkit_error ("read request: %m");
- return set_status (conn, -1);
- }
- if (r == 0) {
- debug ("client closed input socket, closing connection");
- return set_status (conn, 0); /* disconnect */
- }
-
- magic = be32toh (request.magic);
- if (magic != NBD_REQUEST_MAGIC) {
- nbdkit_error ("invalid request: 'magic' field is incorrect (0x%x)",
- magic);
- return set_status (conn, -1);
- }
-
- flags = be16toh (request.flags);
- cmd = be16toh (request.type);
-
- offset = be64toh (request.offset);
- count = be32toh (request.count);
-
- if (cmd == NBD_CMD_DISC) {
- debug ("client sent %s, closing connection", name_of_nbd_cmd (cmd));
- return set_status (conn, 0); /* disconnect */
- }
-
- /* Validate the request. */
- if (!validate_request (conn, cmd, flags, offset, count, &error)) {
- if (cmd == NBD_CMD_WRITE &&
- skip_over_write_buffer (conn->sockin, count) < 0)
- return set_status (conn, -1);
- goto send_reply;
- }
-
- /* Allocate the data buffer used for either read or write requests. */
- if (cmd == NBD_CMD_READ || cmd == NBD_CMD_WRITE) {
- buf = malloc (count);
- if (buf == NULL) {
- perror ("malloc");
- error = ENOMEM;
- if (cmd == NBD_CMD_WRITE &&
- skip_over_write_buffer (conn->sockin, count) < 0)
- return set_status (conn, -1);
- goto send_reply;
- }
- }
-
- /* Receive the write data buffer. */
- if (cmd == NBD_CMD_WRITE) {
- r = conn->recv (conn, buf, count);
- if (r == 0) {
- errno = EBADMSG;
- r = -1;
- }
- if (r == -1) {
- nbdkit_error ("read data: %s: %m", name_of_nbd_cmd (cmd));
- return set_status (conn, -1);
- }
- }
- }
-
- /* Perform the request. Only this part happens inside the request lock. */
- if (quit || !get_status (conn)) {
- error = ESHUTDOWN;
- }
- else {
- lock_request (conn);
- error = handle_request (conn, cmd, flags, offset, count, buf);
- assert ((int) error >= 0);
- unlock_request (conn);
- }
-
- /* Send the reply packet. */
- send_reply:
- if (get_status (conn) < 0)
- return -1;
-
- if (error != 0) {
- /* Since we're about to send only the limited NBD_E* errno to the
- * client, don't lose the information about what really happened
- * on the server side. Make sure there is a way for the operator
- * to retrieve the real error.
- */
- debug ("sending error reply: %s", strerror (error));
- }
-
- /* Currently we prefer to send simple replies for everything except
- * where we have to (ie. NBD_CMD_READ when structured_replies have
- * been negotiated). However this prevents us from sending
- * human-readable error messages to the client, so we should
- * reconsider this in future.
- */
- if (conn->structured_replies && cmd == NBD_CMD_READ) {
- if (!error)
- return send_structured_reply_read (conn, request.handle, cmd,
- buf, count, offset);
- else
- return send_structured_reply_error (conn, request.handle, cmd, error);
- }
- else
- return send_simple_reply (conn, request.handle, cmd, buf, count, error);
-}
-
/* Write buffer to conn->sockout and either succeed completely
* (returns 0) or fail (returns -1).
*/
diff --git a/server/protocol-handshake-newstyle.c b/server/protocol-handshake-newstyle.c
new file mode 100644
index 0000000..db01f7b
--- /dev/null
+++ b/server/protocol-handshake-newstyle.c
@@ -0,0 +1,609 @@
+/* nbdkit
+ * Copyright (C) 2013-2019 Red Hat Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of Red Hat nor the names of its contributors may be
+ * used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "internal.h"
+#include "byte-swapping.h"
+#include "protocol.h"
+
+/* Maximum number of client options we allow before giving up. */
+#define MAX_NR_OPTIONS 32
+
+/* Maximum length of any option data (bytes). */
+#define MAX_OPTION_LENGTH 4096
+
+/* Receive newstyle options. */
+static int
+send_newstyle_option_reply (struct connection *conn,
+ uint32_t option, uint32_t reply)
+{
+ struct fixed_new_option_reply fixed_new_option_reply;
+
+ fixed_new_option_reply.magic = htobe64 (NBD_REP_MAGIC);
+ fixed_new_option_reply.option = htobe32 (option);
+ fixed_new_option_reply.reply = htobe32 (reply);
+ fixed_new_option_reply.replylen = htobe32 (0);
+
+ if (conn->send (conn,
+ &fixed_new_option_reply,
+ sizeof fixed_new_option_reply) == -1) {
+ nbdkit_error ("write: %m");
+ return -1;
+ }
+
+ return 0;
+}
+
+static int
+send_newstyle_option_reply_exportname (struct connection *conn,
+ uint32_t option, uint32_t reply,
+ const char *exportname)
+{
+ struct fixed_new_option_reply fixed_new_option_reply;
+ size_t name_len = strlen (exportname);
+ uint32_t len;
+
+ fixed_new_option_reply.magic = htobe64 (NBD_REP_MAGIC);
+ fixed_new_option_reply.option = htobe32 (option);
+ fixed_new_option_reply.reply = htobe32 (reply);
+ fixed_new_option_reply.replylen = htobe32 (name_len + sizeof (len));
+
+ if (conn->send (conn,
+ &fixed_new_option_reply,
+ sizeof fixed_new_option_reply) == -1) {
+ nbdkit_error ("write: %m");
+ return -1;
+ }
+
+ len = htobe32 (name_len);
+ if (conn->send (conn, &len, sizeof len) == -1) {
+ nbdkit_error ("write: %m");
+ return -1;
+ }
+ if (conn->send (conn, exportname, name_len) == -1) {
+ nbdkit_error ("write: %m");
+ return -1;
+ }
+
+ return 0;
+}
+
+static int
+send_newstyle_option_reply_info_export (struct connection *conn,
+ uint32_t option, uint32_t reply,
+ uint16_t info)
+{
+ struct fixed_new_option_reply fixed_new_option_reply;
+ struct fixed_new_option_reply_info_export export;
+
+ fixed_new_option_reply.magic = htobe64 (NBD_REP_MAGIC);
+ fixed_new_option_reply.option = htobe32 (option);
+ fixed_new_option_reply.reply = htobe32 (reply);
+ fixed_new_option_reply.replylen = htobe32 (sizeof export);
+ export.info = htobe16 (info);
+ export.exportsize = htobe64 (conn->exportsize);
+ export.eflags = htobe16 (conn->eflags);
+
+ if (conn->send (conn,
+ &fixed_new_option_reply,
+ sizeof fixed_new_option_reply) == -1 ||
+ conn->send (conn, &export, sizeof export) == -1) {
+ nbdkit_error ("write: %m");
+ return -1;
+ }
+
+ return 0;
+}
+
+/* Sub-function during negotiate_handshake_newstyle, to uniformly handle
+ * a client hanging up on a message boundary.
+ */
+static int __attribute__ ((format (printf, 4, 5)))
+conn_recv_full (struct connection *conn, void *buf, size_t len,
+ const char *fmt, ...)
+{
+ int r = conn->recv (conn, buf, len);
+ va_list args;
+
+ if (r == -1) {
+ va_start (args, fmt);
+ nbdkit_verror (fmt, args);
+ va_end (args);
+ return -1;
+ }
+ if (r == 0) {
+ /* During negotiation, client EOF on message boundary is less
+ * severe than failure in the middle of the buffer. */
+ debug ("client closed input socket, closing connection");
+ return -1;
+ }
+ return r;
+}
+
+/* Sub-function of negotiate_handshake_newstyle_options below. It
+ * must be called on all non-error paths out of the options for-loop
+ * in that function.
+ */
+static int
+finish_newstyle_options (struct connection *conn)
+{
+ int64_t r;
+
+ r = backend->get_size (backend, conn);
+ if (r == -1)
+ return -1;
+ if (r < 0) {
+ nbdkit_error (".get_size function returned invalid value "
+ "(%" PRIi64 ")", r);
+ return -1;
+ }
+ conn->exportsize = (uint64_t) r;
+
+ if (protocol_compute_eflags (conn, &conn->eflags) < 0)
+ return -1;
+
+ debug ("newstyle negotiation: flags: export 0x%x", conn->eflags);
+ return 0;
+}
+
+static int
+negotiate_handshake_newstyle_options (struct connection *conn)
+{
+ struct new_option new_option;
+ size_t nr_options;
+ uint64_t version;
+ uint32_t option;
+ uint32_t optlen;
+ char data[MAX_OPTION_LENGTH+1];
+ struct new_handshake_finish handshake_finish;
+ const char *optname;
+
+ for (nr_options = 0; nr_options < MAX_NR_OPTIONS; ++nr_options) {
+ if (conn_recv_full (conn, &new_option, sizeof new_option,
+ "reading option: conn->recv: %m") == -1)
+ return -1;
+
+ version = be64toh (new_option.version);
+ if (version != NEW_VERSION) {
+ nbdkit_error ("unknown option version %" PRIx64
+ ", expecting %" PRIx64,
+ version, NEW_VERSION);
+ return -1;
+ }
+
+ /* There is a maximum option length we will accept, regardless
+ * of the option type.
+ */
+ optlen = be32toh (new_option.optlen);
+ if (optlen > MAX_OPTION_LENGTH) {
+ nbdkit_error ("client option data too long (%" PRIu32 ")", optlen);
+ return -1;
+ }
+
+ option = be32toh (new_option.option);
+
+ /* In --tls=require / FORCEDTLS mode the only options allowed
+ * before TLS negotiation are NBD_OPT_ABORT and NBD_OPT_STARTTLS.
+ */
+ if (tls == 2 && !conn->using_tls &&
+ !(option == NBD_OPT_ABORT || option == NBD_OPT_STARTTLS)) {
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_TLS_REQD))
+ return -1;
+ continue;
+ }
+
+ switch (option) {
+ case NBD_OPT_EXPORT_NAME:
+ if (conn_recv_full (conn, data, optlen,
+ "read: %s: %m", name_of_nbd_opt (option)) == -1)
+ return -1;
+ /* Apart from printing it, ignore the export name. */
+ data[optlen] = '\0';
+ debug ("newstyle negotiation: %s: "
+ "client requested export '%s' (ignored)",
+ name_of_nbd_opt (option), data);
+
+ /* We have to finish the handshake by sending handshake_finish. */
+ if (finish_newstyle_options (conn) == -1)
+ return -1;
+
+ memset (&handshake_finish, 0, sizeof handshake_finish);
+ handshake_finish.exportsize = htobe64 (conn->exportsize);
+ handshake_finish.eflags = htobe16 (conn->eflags);
+
+ if (conn->send (conn,
+ &handshake_finish,
+ (conn->cflags & NBD_FLAG_NO_ZEROES)
+ ? offsetof (struct new_handshake_finish, zeroes)
+ : sizeof handshake_finish) == -1) {
+ nbdkit_error ("write: %m");
+ return -1;
+ }
+ break;
+
+ case NBD_OPT_ABORT:
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
+ return -1;
+ debug ("client sent %s to abort the connection",
+ name_of_nbd_opt (option));
+ return -1;
+
+ case NBD_OPT_LIST:
+ if (optlen != 0) {
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
+ == -1)
+ return -1;
+ if (conn_recv_full (conn, data, optlen,
+ "read: %s: %m", name_of_nbd_opt (option)) == -1)
+ return -1;
+ continue;
+ }
+
+ /* Send back the exportname. */
+ debug ("newstyle negotiation: %s: advertising export '%s'",
+ name_of_nbd_opt (option), exportname);
+ if (send_newstyle_option_reply_exportname (conn, option, NBD_REP_SERVER,
+ exportname) == -1)
+ return -1;
+
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
+ return -1;
+ break;
+
+ case NBD_OPT_STARTTLS:
+ if (optlen != 0) {
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
+ == -1)
+ return -1;
+ if (conn_recv_full (conn, data, optlen,
+ "read: %s: %m", name_of_nbd_opt (option)) == -1)
+ return -1;
+ continue;
+ }
+
+ if (tls == 0) { /* --tls=off (NOTLS mode). */
+#ifdef HAVE_GNUTLS
+#define NO_TLS_REPLY NBD_REP_ERR_POLICY
+#else
+#define NO_TLS_REPLY NBD_REP_ERR_UNSUP
+#endif
+ if (send_newstyle_option_reply (conn, option, NO_TLS_REPLY) == -1)
+ return -1;
+ }
+ else /* --tls=on or --tls=require */ {
+ /* We can't upgrade to TLS twice on the same connection. */
+ if (conn->using_tls) {
+ if (send_newstyle_option_reply (conn, option,
+ NBD_REP_ERR_INVALID) == -1)
+ return -1;
+ continue;
+ }
+
+ /* We have to send the (unencrypted) reply before starting
+ * the handshake.
+ */
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
+ return -1;
+
+ /* Upgrade the connection to TLS. Also performs access control. */
+ if (crypto_negotiate_tls (conn, conn->sockin, conn->sockout) == -1)
+ return -1;
+ conn->using_tls = true;
+ debug ("using TLS on this connection");
+ }
+ break;
+
+ case NBD_OPT_INFO:
+ case NBD_OPT_GO:
+ optname = name_of_nbd_opt (option);
+ if (conn_recv_full (conn, data, optlen,
+ "read: %s: %m", optname) == -1)
+ return -1;
+
+ if (optlen < 6) { /* 32 bit export length + 16 bit nr info */
+ debug ("newstyle negotiation: %s option length < 6", optname);
+
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
+ == -1)
+ return -1;
+ continue;
+ }
+
+ {
+ uint32_t exportnamelen;
+ uint16_t nrinfos;
+ uint16_t info;
+ size_t i;
+ CLEANUP_FREE char *requested_exportname = NULL;
+
+ /* Validate the name length and number of INFO requests. */
+ memcpy (&exportnamelen, &data[0], 4);
+ exportnamelen = be32toh (exportnamelen);
+ if (exportnamelen > optlen-6 /* NB optlen >= 6, see above */) {
+ debug ("newstyle negotiation: %s: export name too long", optname);
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
+ == -1)
+ return -1;
+ continue;
+ }
+ memcpy (&nrinfos, &data[exportnamelen+4], 2);
+ nrinfos = be16toh (nrinfos);
+ if (optlen != 4 + exportnamelen + 2 + 2*nrinfos) {
+ debug ("newstyle negotiation: %s: "
+ "number of information requests incorrect", optname);
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
+ == -1)
+ return -1;
+ continue;
+ }
+
+ /* As with NBD_OPT_EXPORT_NAME we print the export name and then
+ * ignore it.
+ */
+ requested_exportname = malloc (exportnamelen+1);
+ if (requested_exportname == NULL) {
+ nbdkit_error ("malloc: %m");
+ return -1;
+ }
+ memcpy (requested_exportname, &data[4], exportnamelen);
+ requested_exportname[exportnamelen] = '\0';
+ debug ("newstyle negotiation: %s: "
+ "client requested export '%s' (ignored)",
+ optname, requested_exportname);
+
+ /* The spec is confusing, but it is required that we send back
+ * NBD_INFO_EXPORT, even if the client did not request it!
+ * qemu client in particular does not request this, but will
+ * fail if we don't send it.
+ */
+ if (finish_newstyle_options (conn) == -1)
+ return -1;
+
+ if (send_newstyle_option_reply_info_export (conn, option,
+ NBD_REP_INFO,
+ NBD_INFO_EXPORT) == -1)
+ return -1;
+
+ /* For now we ignore all other info requests (but we must
+ * ignore NBD_INFO_EXPORT if it was requested, because we
+ * replied already above). Therefore this loop doesn't do
+ * much at the moment.
+ */
+ for (i = 0; i < nrinfos; ++i) {
+ memcpy (&info, &data[4 + exportnamelen + 2 + i*2], 2);
+ info = be16toh (info);
+ switch (info) {
+ case NBD_INFO_EXPORT: /* ignore - reply sent above */ break;
+ default:
+ debug ("newstyle negotiation: %s: "
+ "ignoring NBD_INFO_* request %u (%s)",
+ optname, (unsigned) info, name_of_nbd_info (info));
+ break;
+ }
+ }
+ }
+
+ /* Unlike NBD_OPT_EXPORT_NAME, NBD_OPT_GO sends back an ACK
+ * or ERROR packet.
+ */
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
+ return -1;
+
+ break;
+
+ case NBD_OPT_STRUCTURED_REPLY:
+ if (optlen != 0) {
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
+ == -1)
+ return -1;
+ if (conn_recv_full (conn, data, optlen,
+ "read: %s: %m", name_of_nbd_opt (option)) == -1)
+ return -1;
+ continue;
+ }
+
+ debug ("newstyle negotiation: %s: client requested structured replies",
+ name_of_nbd_opt (option));
+
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
+ return -1;
+
+ conn->structured_replies = true;
+ break;
+
+ case NBD_OPT_LIST_META_CONTEXT:
+ case NBD_OPT_SET_META_CONTEXT:
+ {
+ uint32_t opt_index;
+ uint32_t exportnamelen;
+ uint32_t nr_queries;
+ uint32_t querylen;
+ const char *what;
+
+ optname = name_of_nbd_opt (option);
+ if (conn_recv_full (conn, data, optlen, "read: %s: %m", optname) == -1)
+ return -1;
+
+ if (!conn->structured_replies) {
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
+ == -1)
+ return -1;
+ continue;
+ }
+
+ /* Minimum length of the option payload is:
+ * 32 bit export name length followed by empty export name
+ * + 32 bit number of queries followed by no queries
+ * = 8 bytes.
+ */
+ what = "optlen < 8";
+ if (optlen < 8) {
+ opt_meta_invalid_option_len:
+ debug ("newstyle negotiation: %s: invalid option length: %s",
+ optname, what);
+
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_INVALID)
+ == -1)
+ return -1;
+ continue;
+ }
+
+ /* Discard the export name. */
+ memcpy (&exportnamelen, &data[0], 4);
+ exportnamelen = be32toh (exportnamelen);
+ opt_index = 4 + exportnamelen;
+
+ /* Read the number of queries. */
+ what = "reading number of queries";
+ if (opt_index+4 > optlen)
+ goto opt_meta_invalid_option_len;
+ memcpy (&nr_queries, &data[opt_index], 4);
+ nr_queries = be32toh (nr_queries);
+ opt_index += 4;
+
+ /* for LIST: nr_queries == 0 means return all meta contexts
+ * for SET: nr_queries == 0 means reset all contexts
+ */
+ if (nr_queries == 0) {
+ /* Nothing is supported now. */
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
+ return -1;
+ }
+ else {
+ /* Read and answer each query. */
+ while (nr_queries > 0) {
+ what = "reading query string length";
+ if (opt_index+4 > optlen)
+ goto opt_meta_invalid_option_len;
+ memcpy (&querylen, &data[opt_index], 4);
+ querylen = be32toh (querylen);
+ opt_index += 4;
+ what = "reading query string";
+ if (opt_index + querylen > optlen)
+ goto opt_meta_invalid_option_len;
+
+ debug ("newstyle negotiation: %s: %s %.*s",
+ optname,
+ option == NBD_OPT_LIST_META_CONTEXT ? "query" : "set",
+ (int) querylen, &data[opt_index]);
+
+ /* Ignore query - nothing is supported. */
+
+ opt_index += querylen;
+ nr_queries--;
+ }
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
+ return -1;
+ }
+ }
+ break;
+
+ default:
+ /* Unknown option. */
+ if (send_newstyle_option_reply (conn, option, NBD_REP_ERR_UNSUP) == -1)
+ return -1;
+ if (conn_recv_full (conn, data, optlen,
+ "reading unknown option data: conn->recv: %m") == -1)
+ return -1;
+ }
+
+ /* Note, since it's not very clear from the protocol doc, that the
+ * client must send NBD_OPT_EXPORT_NAME or NBD_OPT_GO last, and
+ * that ends option negotiation.
+ */
+ if (option == NBD_OPT_EXPORT_NAME || option == NBD_OPT_GO)
+ break;
+ }
+
+ if (nr_options >= MAX_NR_OPTIONS) {
+ nbdkit_error ("client exceeded maximum number of options (%d)",
+ MAX_NR_OPTIONS);
+ return -1;
+ }
+
+ /* In --tls=require / FORCEDTLS mode, we must have upgraded to TLS
+ * by the time we finish option negotiation. If not, give up.
+ */
+ if (tls == 2 && !conn->using_tls) {
+ nbdkit_error ("non-TLS client tried to connect in --tls=require mode");
+ return -1;
+ }
+
+ return 0;
+}
+
+int
+protocol_handshake_newstyle (struct connection *conn)
+{
+ struct new_handshake handshake;
+ uint16_t gflags;
+
+ gflags = NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES;
+
+ debug ("newstyle negotiation: flags: global 0x%x", gflags);
+
+ memcpy (handshake.nbdmagic, "NBDMAGIC", 8);
+ handshake.version = htobe64 (NEW_VERSION);
+ handshake.gflags = htobe16 (gflags);
+
+ if (conn->send (conn, &handshake, sizeof handshake) == -1) {
+ nbdkit_error ("write: %m");
+ return -1;
+ }
+
+ /* Client now sends us its 32 bit flags word ... */
+ if (conn_recv_full (conn, &conn->cflags, sizeof conn->cflags,
+ "reading initial client flags: conn->recv: %m") == -1)
+ return -1;
+ conn->cflags = be32toh (conn->cflags);
+ /* ... which we check for accuracy. */
+ debug ("newstyle negotiation: client flags: 0x%x", conn->cflags);
+ if (conn->cflags & ~gflags) {
+ nbdkit_error ("client requested unknown flags 0x%x", conn->cflags);
+ return -1;
+ }
+
+ /* Receive newstyle options. */
+ if (negotiate_handshake_newstyle_options (conn) == -1)
+ return -1;
+
+ return 0;
+}
diff --git a/server/protocol-handshake-oldstyle.c b/server/protocol-handshake-oldstyle.c
new file mode 100644
index 0000000..c5dd256
--- /dev/null
+++ b/server/protocol-handshake-oldstyle.c
@@ -0,0 +1,94 @@
+/* nbdkit
+ * Copyright (C) 2013-2019 Red Hat Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of Red Hat nor the names of its contributors may be
+ * used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "internal.h"
+#include "byte-swapping.h"
+#include "protocol.h"
+
+int
+protocol_handshake_oldstyle (struct connection *conn)
+{
+ struct old_handshake handshake;
+ int64_t r;
+ uint64_t exportsize;
+ uint16_t gflags, eflags;
+
+ /* In --tls=require / FORCEDTLS mode, old style handshakes are
+ * rejected because they cannot support TLS.
+ */
+ if (tls == 2) {
+ nbdkit_error ("non-TLS client tried to connect in --tls=require mode");
+ return -1;
+ }
+
+ r = backend->get_size (backend, conn);
+ if (r == -1)
+ return -1;
+ if (r < 0) {
+ nbdkit_error (".get_size function returned invalid value "
+ "(%" PRIi64 ")", r);
+ return -1;
+ }
+ exportsize = (uint64_t) r;
+ conn->exportsize = exportsize;
+
+ gflags = 0;
+ if (protocol_compute_eflags (conn, &eflags) < 0)
+ return -1;
+
+ debug ("oldstyle negotiation: flags: global 0x%x export 0x%x",
+ gflags, eflags);
+
+ memset (&handshake, 0, sizeof handshake);
+ memcpy (handshake.nbdmagic, "NBDMAGIC", 8);
+ handshake.version = htobe64 (OLD_VERSION);
+ handshake.exportsize = htobe64 (exportsize);
+ handshake.gflags = htobe16 (gflags);
+ handshake.eflags = htobe16 (eflags);
+
+ if (conn->send (conn, &handshake, sizeof handshake) == -1) {
+ nbdkit_error ("write: %m");
+ return -1;
+ }
+
+ return 0;
+}
diff --git a/server/protocol-handshake.c b/server/protocol-handshake.c
new file mode 100644
index 0000000..79a5999
--- /dev/null
+++ b/server/protocol-handshake.c
@@ -0,0 +1,130 @@
+/* nbdkit
+ * Copyright (C) 2013-2019 Red Hat Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of Red Hat nor the names of its contributors may be
+ * used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "internal.h"
+#include "byte-swapping.h"
+#include "protocol.h"
+
+/* eflags calculation is the same between oldstyle and newstyle
+ * protocols.
+ */
+int
+protocol_compute_eflags (struct connection *conn, uint16_t *flags)
+{
+ uint16_t eflags = NBD_FLAG_HAS_FLAGS;
+ int fl;
+
+ fl = backend->can_write (backend, conn);
+ if (fl == -1)
+ return -1;
+ if (readonly || !fl) {
+ eflags |= NBD_FLAG_READ_ONLY;
+ conn->readonly = true;
+ }
+ if (!conn->readonly) {
+ fl = backend->can_zero (backend, conn);
+ if (fl == -1)
+ return -1;
+ if (fl) {
+ eflags |= NBD_FLAG_SEND_WRITE_ZEROES;
+ conn->can_zero = true;
+ }
+
+ fl = backend->can_trim (backend, conn);
+ if (fl == -1)
+ return -1;
+ if (fl) {
+ eflags |= NBD_FLAG_SEND_TRIM;
+ conn->can_trim = true;
+ }
+
+ fl = backend->can_fua (backend, conn);
+ if (fl == -1)
+ return -1;
+ if (fl) {
+ eflags |= NBD_FLAG_SEND_FUA;
+ conn->can_fua = true;
+ }
+ }
+
+ fl = backend->can_flush (backend, conn);
+ if (fl == -1)
+ return -1;
+ if (fl) {
+ eflags |= NBD_FLAG_SEND_FLUSH;
+ conn->can_flush = true;
+ }
+
+ fl = backend->is_rotational (backend, conn);
+ if (fl == -1)
+ return -1;
+ if (fl) {
+ eflags |= NBD_FLAG_ROTATIONAL;
+ conn->is_rotational = true;
+ }
+
+ fl = backend->can_multi_conn (backend, conn);
+ if (fl == -1)
+ return -1;
+ if (fl) {
+ eflags |= NBD_FLAG_CAN_MULTI_CONN;
+ conn->can_multi_conn = true;
+ }
+
+ *flags = eflags;
+ return 0;
+}
+
+int
+protocol_handshake (struct connection *conn)
+{
+ int r;
+
+ lock_request (conn);
+ if (!newstyle)
+ r = protocol_handshake_oldstyle (conn);
+ else
+ r = protocol_handshake_newstyle (conn);
+ unlock_request (conn);
+
+ return r;
+}
diff --git a/server/protocol.c b/server/protocol.c
new file mode 100644
index 0000000..f117d42
--- /dev/null
+++ b/server/protocol.c
@@ -0,0 +1,515 @@
+/* nbdkit
+ * Copyright (C) 2013-2019 Red Hat Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of Red Hat nor the names of its contributors may be
+ * used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <assert.h>
+
+#include "internal.h"
+#include "byte-swapping.h"
+#include "protocol.h"
+
+/* Maximum read or write request that we will handle. */
+#define MAX_REQUEST_SIZE (64 * 1024 * 1024)
+
+static bool
+valid_range (struct connection *conn, uint64_t offset, uint32_t count)
+{
+ uint64_t exportsize = conn->exportsize;
+
+ return count > 0 && offset <= exportsize && offset + count <= exportsize;
+}
+
+static bool
+validate_request (struct connection *conn,
+ uint16_t cmd, uint16_t flags, uint64_t offset, uint32_t count,
+ uint32_t *error)
+{
+ /* Readonly connection? */
+ if (conn->readonly &&
+ (cmd == NBD_CMD_WRITE || cmd == NBD_CMD_TRIM ||
+ cmd == NBD_CMD_WRITE_ZEROES)) {
+ nbdkit_error ("invalid request: %s: write request on readonly connection",
+ name_of_nbd_cmd (cmd));
+ *error = EROFS;
+ return false;
+ }
+
+ /* Validate cmd, offset, count. */
+ switch (cmd) {
+ case NBD_CMD_READ:
+ case NBD_CMD_WRITE:
+ case NBD_CMD_TRIM:
+ case NBD_CMD_WRITE_ZEROES:
+ if (!valid_range (conn, offset, count)) {
+ /* XXX Allow writes to extend the disk? */
+ nbdkit_error ("invalid request: %s: offset and count are out of range: "
+ "offset=%" PRIu64 " count=%" PRIu32,
+ name_of_nbd_cmd (cmd), offset, count);
+ *error = (cmd == NBD_CMD_WRITE ||
+ cmd == NBD_CMD_WRITE_ZEROES) ? ENOSPC : EINVAL;
+ return false;
+ }
+ break;
+
+ case NBD_CMD_FLUSH:
+ if (offset != 0 || count != 0) {
+ nbdkit_error ("invalid request: %s: expecting offset and count = 0",
+ name_of_nbd_cmd (cmd));
+ *error = EINVAL;
+ return false;
+ }
+ break;
+
+ default:
+ nbdkit_error ("invalid request: unknown command (%" PRIu32 ") ignored",
+ cmd);
+ *error = EINVAL;
+ return false;
+ }
+
+ /* Validate flags */
+ if (flags & ~(NBD_CMD_FLAG_FUA | NBD_CMD_FLAG_NO_HOLE)) {
+ nbdkit_error ("invalid request: unknown flag (0x%x)", flags);
+ *error = EINVAL;
+ return false;
+ }
+ if ((flags & NBD_CMD_FLAG_NO_HOLE) &&
+ cmd != NBD_CMD_WRITE_ZEROES) {
+ nbdkit_error ("invalid request: NO_HOLE flag needs WRITE_ZEROES request");
+ *error = EINVAL;
+ return false;
+ }
+ if (!conn->can_fua && (flags & NBD_CMD_FLAG_FUA)) {
+ nbdkit_error ("invalid request: FUA flag not supported");
+ *error = EINVAL;
+ return false;
+ }
+
+ /* Refuse over-large read and write requests. */
+ if ((cmd == NBD_CMD_WRITE || cmd == NBD_CMD_READ) &&
+ count > MAX_REQUEST_SIZE) {
+ nbdkit_error ("invalid request: %s: data request is too large (%" PRIu32
+ " > %d)",
+ name_of_nbd_cmd (cmd), count, MAX_REQUEST_SIZE);
+ *error = ENOMEM;
+ return false;
+ }
+
+ /* Flush allowed? */
+ if (!conn->can_flush && cmd == NBD_CMD_FLUSH) {
+ nbdkit_error ("invalid request: %s: flush operation not supported",
+ name_of_nbd_cmd (cmd));
+ *error = EINVAL;
+ return false;
+ }
+
+ /* Trim allowed? */
+ if (!conn->can_trim && cmd == NBD_CMD_TRIM) {
+ nbdkit_error ("invalid request: %s: trim operation not supported",
+ name_of_nbd_cmd (cmd));
+ *error = EINVAL;
+ return false;
+ }
+
+ /* Zero allowed? */
+ if (!conn->can_zero && cmd == NBD_CMD_WRITE_ZEROES) {
+ nbdkit_error ("invalid request: %s: write zeroes operation not supported",
+ name_of_nbd_cmd (cmd));
+ *error = EINVAL;
+ return false;
+ }
+
+ return true; /* Command validates. */
+}
+
+/* This is called with the request lock held to actually execute the
+ * request (by calling the plugin). Note that the request fields have
+ * been validated already in 'validate_request' so we don't have to
+ * check them again. 'buf' is either the data to be written or the
+ * data to be returned, and points to a buffer of size 'count' bytes.
+ *
+ * In all cases, the return value is the system errno value that will
+ * later be converted to the nbd error to send back to the client (0
+ * for success).
+ */
+static uint32_t
+handle_request (struct connection *conn,
+ uint16_t cmd, uint16_t flags, uint64_t offset, uint32_t count,
+ void *buf)
+{
+ uint32_t f = 0;
+ bool fua = conn->can_fua && (flags & NBD_CMD_FLAG_FUA);
+ int err = 0;
+
+ /* Clear the error, so that we know if the plugin calls
+ * nbdkit_set_error() or relied on errno. */
+ threadlocal_set_error (0);
+
+ switch (cmd) {
+ case NBD_CMD_READ:
+ if (backend->pread (backend, conn, buf, count, offset, 0, &err) == -1)
+ return err;
+ break;
+
+ case NBD_CMD_WRITE:
+ if (fua)
+ f |= NBDKIT_FLAG_FUA;
+ if (backend->pwrite (backend, conn, buf, count, offset, f, &err) == -1)
+ return err;
+ break;
+
+ case NBD_CMD_FLUSH:
+ if (backend->flush (backend, conn, 0, &err) == -1)
+ return err;
+ break;
+
+ case NBD_CMD_TRIM:
+ if (fua)
+ f |= NBDKIT_FLAG_FUA;
+ if (backend->trim (backend, conn, count, offset, f, &err) == -1)
+ return err;
+ break;
+
+ case NBD_CMD_WRITE_ZEROES:
+ if (!(flags & NBD_CMD_FLAG_NO_HOLE))
+ f |= NBDKIT_FLAG_MAY_TRIM;
+ if (fua)
+ f |= NBDKIT_FLAG_FUA;
+ if (backend->zero (backend, conn, count, offset, f, &err) == -1)
+ return err;
+ break;
+
+ default:
+ abort ();
+ }
+
+ return 0;
+}
+
+static int
+skip_over_write_buffer (int sock, size_t count)
+{
+ char buf[BUFSIZ];
+ ssize_t r;
+
+ if (count > MAX_REQUEST_SIZE * 2) {
+ nbdkit_error ("write request too large to skip");
+ return -1;
+ }
+
+ while (count > 0) {
+ r = read (sock, buf, count > BUFSIZ ? BUFSIZ : count);
+ if (r == -1) {
+ nbdkit_error ("skipping write buffer: %m");
+ return -1;
+ }
+ if (r == 0) {
+ nbdkit_error ("unexpected early EOF");
+ errno = EBADMSG;
+ return -1;
+ }
+ count -= r;
+ }
+ return 0;
+}
+
+/* Convert a system errno to an NBD_E* error code. */
+static int
+nbd_errno (int error)
+{
+ switch (error) {
+ case 0:
+ return NBD_SUCCESS;
+ case EROFS:
+ case EPERM:
+ return NBD_EPERM;
+ case EIO:
+ return NBD_EIO;
+ case ENOMEM:
+ return NBD_ENOMEM;
+#ifdef EDQUOT
+ case EDQUOT:
+#endif
+ case EFBIG:
+ case ENOSPC:
+ return NBD_ENOSPC;
+#ifdef ESHUTDOWN
+ case ESHUTDOWN:
+ return NBD_ESHUTDOWN;
+#endif
+ case EINVAL:
+ default:
+ return NBD_EINVAL;
+ }
+}
+
+static int
+send_simple_reply (struct connection *conn,
+ uint64_t handle, uint16_t cmd,
+ const char *buf, uint32_t count,
+ uint32_t error)
+{
+ ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&conn->write_lock);
+ struct simple_reply reply;
+ int r;
+
+ reply.magic = htobe32 (NBD_SIMPLE_REPLY_MAGIC);
+ reply.handle = handle;
+ reply.error = htobe32 (nbd_errno (error));
+
+ r = conn->send (conn, &reply, sizeof reply);
+ if (r == -1) {
+ nbdkit_error ("write reply: %s: %m", name_of_nbd_cmd (cmd));
+ return connection_set_status (conn, -1);
+ }
+
+ /* Send the read data buffer. */
+ if (cmd == NBD_CMD_READ && !error) {
+ r = conn->send (conn, buf, count);
+ if (r == -1) {
+ nbdkit_error ("write data: %s: %m", name_of_nbd_cmd (cmd));
+ return connection_set_status (conn, -1);
+ }
+ }
+
+ return 1; /* command processed ok */
+}
+
+static int
+send_structured_reply_read (struct connection *conn,
+ uint64_t handle, uint16_t cmd,
+ const char *buf, uint32_t count, uint64_t offset)
+{
+ /* Once we are really using structured replies and sending data back
+ * in chunks, we'll be able to grab the write lock for each chunk,
+ * allowing other threads to interleave replies. As we're not doing
+ * that yet we acquire the lock for the whole function.
+ */
+ ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&conn->write_lock);
+ struct structured_reply reply;
+ struct structured_reply_offset_data offset_data;
+ int r;
+
+ assert (cmd == NBD_CMD_READ);
+
+ reply.magic = htobe32 (NBD_STRUCTURED_REPLY_MAGIC);
+ reply.handle = handle;
+ reply.flags = htobe16 (NBD_REPLY_FLAG_DONE);
+ reply.type = htobe16 (NBD_REPLY_TYPE_OFFSET_DATA);
+ reply.length = htobe32 (count + sizeof offset_data);
+
+ r = conn->send (conn, &reply, sizeof reply);
+ if (r == -1) {
+ nbdkit_error ("write reply: %s: %m", name_of_nbd_cmd (cmd));
+ return connection_set_status (conn, -1);
+ }
+
+ /* Send the offset + read data buffer. */
+ offset_data.offset = htobe64 (offset);
+ r = conn->send (conn, &offset_data, sizeof offset_data);
+ if (r == -1) {
+ nbdkit_error ("write data: %s: %m", name_of_nbd_cmd (cmd));
+ return connection_set_status (conn, -1);
+ }
+
+ r = conn->send (conn, buf, count);
+ if (r == -1) {
+ nbdkit_error ("write data: %s: %m", name_of_nbd_cmd (cmd));
+ return connection_set_status (conn, -1);
+ }
+
+ return 1; /* command processed ok */
+}
+
+static int
+send_structured_reply_error (struct connection *conn,
+ uint64_t handle, uint16_t cmd, uint32_t error)
+{
+ ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&conn->write_lock);
+ struct structured_reply reply;
+ struct structured_reply_error error_data;
+ int r;
+
+ reply.magic = htobe32 (NBD_STRUCTURED_REPLY_MAGIC);
+ reply.handle = handle;
+ reply.flags = htobe16 (NBD_REPLY_FLAG_DONE);
+ reply.type = htobe16 (NBD_REPLY_TYPE_ERROR);
+ reply.length = htobe32 (0 /* no human readable error */ + sizeof error_data);
+
+ r = conn->send (conn, &reply, sizeof reply);
+ if (r == -1) {
+ nbdkit_error ("write error reply: %m");
+ return connection_set_status (conn, -1);
+ }
+
+ /* Send the error. */
+ error_data.error = htobe32 (error);
+ error_data.len = htobe16 (0);
+ r = conn->send (conn, &error_data, sizeof error_data);
+ if (r == -1) {
+ nbdkit_error ("write data: %s: %m", name_of_nbd_cmd (cmd));
+ return connection_set_status (conn, -1);
+ }
+ /* No human readable error message at the moment. */
+
+ return 1; /* command processed ok */
+}
+
+int
+protocol_recv_request_send_reply (struct connection *conn)
+{
+ int r;
+ struct request request;
+ uint16_t cmd, flags;
+ uint32_t magic, count, error = 0;
+ uint64_t offset;
+ CLEANUP_FREE char *buf = NULL;
+
+ /* Read the request packet. */
+ {
+ ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&conn->read_lock);
+ r = connection_get_status (conn);
+ if (r <= 0)
+ return r;
+ r = conn->recv (conn, &request, sizeof request);
+ if (r == -1) {
+ nbdkit_error ("read request: %m");
+ return connection_set_status (conn, -1);
+ }
+ if (r == 0) {
+ debug ("client closed input socket, closing connection");
+ return connection_set_status (conn, 0); /* disconnect */
+ }
+
+ magic = be32toh (request.magic);
+ if (magic != NBD_REQUEST_MAGIC) {
+ nbdkit_error ("invalid request: 'magic' field is incorrect (0x%x)",
+ magic);
+ return connection_set_status (conn, -1);
+ }
+
+ flags = be16toh (request.flags);
+ cmd = be16toh (request.type);
+
+ offset = be64toh (request.offset);
+ count = be32toh (request.count);
+
+ if (cmd == NBD_CMD_DISC) {
+ debug ("client sent %s, closing connection", name_of_nbd_cmd (cmd));
+ return connection_set_status (conn, 0); /* disconnect */
+ }
+
+ /* Validate the request. */
+ if (!validate_request (conn, cmd, flags, offset, count, &error)) {
+ if (cmd == NBD_CMD_WRITE &&
+ skip_over_write_buffer (conn->sockin, count) < 0)
+ return connection_set_status (conn, -1);
+ goto send_reply;
+ }
+
+ /* Allocate the data buffer used for either read or write requests. */
+ if (cmd == NBD_CMD_READ || cmd == NBD_CMD_WRITE) {
+ buf = malloc (count);
+ if (buf == NULL) {
+ perror ("malloc");
+ error = ENOMEM;
+ if (cmd == NBD_CMD_WRITE &&
+ skip_over_write_buffer (conn->sockin, count) < 0)
+ return connection_set_status (conn, -1);
+ goto send_reply;
+ }
+ }
+
+ /* Receive the write data buffer. */
+ if (cmd == NBD_CMD_WRITE) {
+ r = conn->recv (conn, buf, count);
+ if (r == 0) {
+ errno = EBADMSG;
+ r = -1;
+ }
+ if (r == -1) {
+ nbdkit_error ("read data: %s: %m", name_of_nbd_cmd (cmd));
+ return connection_set_status (conn, -1);
+ }
+ }
+ }
+
+ /* Perform the request. Only this part happens inside the request lock. */
+ if (quit || !connection_get_status (conn)) {
+ error = ESHUTDOWN;
+ }
+ else {
+ lock_request (conn);
+ error = handle_request (conn, cmd, flags, offset, count, buf);
+ assert ((int) error >= 0);
+ unlock_request (conn);
+ }
+
+ /* Send the reply packet. */
+ send_reply:
+ if (connection_get_status (conn) < 0)
+ return -1;
+
+ if (error != 0) {
+ /* Since we're about to send only the limited NBD_E* errno to the
+ * client, don't lose the information about what really happened
+ * on the server side. Make sure there is a way for the operator
+ * to retrieve the real error.
+ */
+ debug ("sending error reply: %s", strerror (error));
+ }
+
+ /* Currently we prefer to send simple replies for everything except
+ * where we have to (ie. NBD_CMD_READ when structured_replies have
+ * been negotiated). However this prevents us from sending
+ * human-readable error messages to the client, so we should
+ * reconsider this in future.
+ */
+ if (conn->structured_replies && cmd == NBD_CMD_READ) {
+ if (!error)
+ return send_structured_reply_read (conn, request.handle, cmd,
+ buf, count, offset);
+ else
+ return send_structured_reply_error (conn, request.handle, cmd, error);
+ }
+ else
+ return send_simple_reply (conn, request.handle, cmd, buf, count, error);
+}
diff --git a/server/Makefile.am b/server/Makefile.am
index b198afb..5eb575e 100644
--- a/server/Makefile.am
+++ b/server/Makefile.am
@@ -52,6 +52,10 @@ nbdkit_SOURCES = \
main.c \
options.h \
plugins.c \
+ protocol.c \
+ protocol-handshake.c \
+ protocol-handshake-oldstyle.c \
+ protocol-handshake-newstyle.c \
protocol.h \
protostrings.c \
quit.c \
--
2.20.1
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