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nbd: Share common reply-sending code in server 

Rather than open-coding NBD_REP_SERVER, reuse the code we
already have by adding a length parameter.  Additionally,
the refactoring will make adding NBD_OPT_GO in a later patch
easier.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-7-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Eric Blake 2016-10-14 13:33:08 -05:00 committed by Paolo Bonzini
parent ed2dd91267
commit 526e5c6559
1 changed files with 27 additions and 25 deletions
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52
nbd/server.c
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@ -196,12 +196,15 @@ static ssize_t nbd_negotiate_drop_sync(QIOChannel *ioc, size_t size)
*/
static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt)
/* Send a reply header, including length, but no payload.
* Return -errno on error, 0 on success. */
static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type,
uint32_t opt, uint32_t len)
{
uint64_t magic;
uint32_t len;
TRACE("Reply opt=%" PRIx32 " type=%" PRIx32, type, opt);
TRACE("Reply opt=%" PRIx32 " type=%" PRIx32 " len=%" PRIu32,
type, opt, len);
magic = cpu_to_be64(NBD_REP_MAGIC);
if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
@ -218,7 +221,7 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt)
LOG("write failed (rep type)");
return -EINVAL;
}
len = cpu_to_be32(0);
len = cpu_to_be32(len);
if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
LOG("write failed (rep data length)");
return -EINVAL;
@ -226,37 +229,32 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt)
return 0;
}
/* Send a reply header with default 0 length.
* Return -errno on error, 0 on success. */
static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt)
{
return nbd_negotiate_send_rep_len(ioc, type, opt, 0);
}
/* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
* Return -errno on error, 0 on success. */
static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
{
uint64_t magic;
size_t name_len, desc_len;
uint32_t opt, type, len;
uint32_t len;
const char *name = exp->name ? exp->name : "";
const char *desc = exp->description ? exp->description : "";
int rc;
TRACE("Advertising export name '%s' description '%s'", name, desc);
name_len = strlen(name);
desc_len = strlen(desc);
magic = cpu_to_be64(NBD_REP_MAGIC);
if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
LOG("write failed (magic)");
return -EINVAL;
}
opt = cpu_to_be32(NBD_OPT_LIST);
if (nbd_negotiate_write(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
LOG("write failed (opt)");
return -EINVAL;
}
type = cpu_to_be32(NBD_REP_SERVER);
if (nbd_negotiate_write(ioc, &type, sizeof(type)) != sizeof(type)) {
LOG("write failed (reply type)");
return -EINVAL;
}
len = cpu_to_be32(name_len + desc_len + sizeof(len));
if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
LOG("write failed (length)");
return -EINVAL;
len = name_len + desc_len + sizeof(len);
rc = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, len);
if (rc < 0) {
return rc;
}
len = cpu_to_be32(name_len);
if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
LOG("write failed (name length)");
@ -273,6 +271,8 @@ static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
return 0;
}
/* Process the NBD_OPT_LIST command, with a potential series of replies.
* Return -errno on error, 0 on success. */
static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length)
{
NBDExport *exp;
@ -382,6 +382,8 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
}
/* Process all NBD_OPT_* client option commands.
* Return -errno on error, 0 on success. */
static int nbd_negotiate_options(NBDClient *client)
{
uint32_t flags;