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[Qemu-devel] [PATCH 07/15] nbd: invert client logic for negotiating prot
From: |
Daniel P. Berrange |
Subject: |
[Qemu-devel] [PATCH 07/15] nbd: invert client logic for negotiating protocol version |
Date: |
Fri, 27 Nov 2015 12:20:45 +0000 |
The nbd_receive_negotiate() method takes different code
paths based on whether 'name == NULL', and then checks
the expected protocol version in each branch.
This patch inverts the logic, so that it takes different
code paths based on what protocol version it receives and
then checks if name is NULL or not as needed.
This facilitates later code which allows the client to
be caapble of using the new style protocol regardless
of whether an export name is listed or not.
Signed-off-by: Daniel P. Berrange <address@hidden>
---
nbd.c | 60 +++++++++++++++++++++++++++++-------------------------------
1 file changed, 29 insertions(+), 31 deletions(-)
diff --git a/nbd.c b/nbd.c
index 701b951..bdfc45e 100644
--- a/nbd.c
+++ b/nbd.c
@@ -682,20 +682,11 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char
*name, uint32_t *flags,
magic = be64_to_cpu(magic);
TRACE("Magic is 0x%" PRIx64, magic);
- if (name) {
+ if (magic == NBD_OPTS_MAGIC) {
uint32_t reserved = 0;
uint32_t opt;
uint32_t namesize;
- TRACE("Checking magic (opts_magic)");
- if (magic != NBD_OPTS_MAGIC) {
- if (magic == NBD_CLIENT_MAGIC) {
- error_setg(errp, "Server does not support export names");
- } else {
- error_setg(errp, "Bad magic received");
- }
- goto fail;
- }
if (read_sync(ioc, &tmp, sizeof(tmp)) != sizeof(tmp)) {
error_setg(errp, "Failed to read server flags");
goto fail;
@@ -708,6 +699,10 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char
*name, uint32_t *flags,
goto fail;
}
/* write the export name */
+ if (!name) {
+ error_setg(errp, "Server requires an export name");
+ goto fail;
+ }
magic = cpu_to_be64(magic);
if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
error_setg(errp, "Failed to send export name magic");
@@ -728,39 +723,42 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char
*name, uint32_t *flags,
error_setg(errp, "Failed to send export name");
goto fail;
}
- } else {
- TRACE("Checking magic (cli_magic)");
- if (magic != NBD_CLIENT_MAGIC) {
- if (magic == NBD_OPTS_MAGIC) {
- error_setg(errp, "Server requires an export name");
- } else {
- error_setg(errp, "Bad magic received");
- }
+ if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
+ error_setg(errp, "Failed to read export length");
goto fail;
}
- }
+ *size = be64_to_cpu(s);
+ TRACE("Size is %" PRIu64, *size);
- if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
- error_setg(errp, "Failed to read export length");
- goto fail;
- }
- *size = be64_to_cpu(s);
- TRACE("Size is %" PRIu64, *size);
+ if (read_sync(ioc, &tmp, sizeof(tmp)) != sizeof(tmp)) {
+ error_setg(errp, "Failed to read export flags");
+ goto fail;
+ }
+ *flags |= be16_to_cpu(tmp);
+ } else if (magic == NBD_CLIENT_MAGIC) {
+ if (name) {
+ error_setg(errp, "Server does not support export names");
+ goto fail;
+ }
+
+ if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
+ error_setg(errp, "Failed to read export length");
+ goto fail;
+ }
+ *size = be64_to_cpu(s);
+ TRACE("Size is %" PRIu64, *size);
- if (!name) {
if (read_sync(ioc, flags, sizeof(*flags)) != sizeof(*flags)) {
error_setg(errp, "Failed to read export flags");
goto fail;
}
*flags = be32_to_cpup(flags);
} else {
- if (read_sync(ioc, &tmp, sizeof(tmp)) != sizeof(tmp)) {
- error_setg(errp, "Failed to read export flags");
- goto fail;
- }
- *flags |= be16_to_cpu(tmp);
+ error_setg(errp, "Bad magic received");
+ goto fail;
}
+
if (read_sync(ioc, &buf, 124) != 124) {
error_setg(errp, "Failed to read reserved block");
goto fail;
--
2.5.0
- [Qemu-devel] [PATCH 00/15] Implement TLS support to QEMU NBD server & client, Daniel P. Berrange, 2015/11/27
- [Qemu-devel] [PATCH 01/15] qom: add user_creatable_add & user_creatable_del methods, Daniel P. Berrange, 2015/11/27
- [Qemu-devel] [PATCH 04/15] nbd: convert qemu-nbd server to use I/O channels for connection setup, Daniel P. Berrange, 2015/11/27
- [Qemu-devel] [PATCH 03/15] nbd: convert block client to use I/O channels for connection setup, Daniel P. Berrange, 2015/11/27
- [Qemu-devel] [PATCH 05/15] nbd: convert blockdev NBD server to use I/O channels for connection setup, Daniel P. Berrange, 2015/11/27
- [Qemu-devel] [PATCH 07/15] nbd: invert client logic for negotiating protocol version,
Daniel P. Berrange <=
- [Qemu-devel] [PATCH 09/15] nbd: make client request fixed new style if advertized, Daniel P. Berrange, 2015/11/27
- [Qemu-devel] [PATCH 02/15] qemu-nbd: add support for --object command line arg, Daniel P. Berrange, 2015/11/27
- [Qemu-devel] [PATCH 08/15] nbd: make server compliant with fixed newstyle spec, Daniel P. Berrange, 2015/11/27
- [Qemu-devel] [PATCH 06/15] nbd: convert to using I/O channels for actual socket I/O, Daniel P. Berrange, 2015/11/27
- [Qemu-devel] [PATCH 10/15] nbd: allow setting of an export name for qemu-nbd server, Daniel P. Berrange, 2015/11/27
- [Qemu-devel] [PATCH 14/15] nbd: enable use of TLS with qemu-nbd server, Daniel P. Berrange, 2015/11/27
- [Qemu-devel] [PATCH 12/15] nbd: implement TLS support in the protocol negotiation, Daniel P. Berrange, 2015/11/27
- [Qemu-devel] [PATCH 11/15] nbd: pick first exported volume if no export name is requested, Daniel P. Berrange, 2015/11/27
- [Qemu-devel] [PATCH 13/15] nbd: enable use of TLS with NBD block driver, Daniel P. Berrange, 2015/11/27