Rather than open-coding NBD_REP_SERVER, reuse the code we
already have by adding a length parameter. The code gets
longer because of added comments, but the refactoring will
make adding NBD_OPT_GO in a later patch easier.
Signed-off-by: Eric Blake <ebl...@redhat.com>
---
nbd/server.c | 59 +++++++++++++++++++++++++++++------------------------------
1 file changed, 29 insertions(+), 30 deletions(-)
diff --git a/nbd/server.c b/nbd/server.c
index c8666ab..69724c9 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -192,12 +192,15 @@ 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 to kill connection, 0 to continue negotiation */
+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)) {
@@ -214,7 +217,7 @@ 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;
@@ -222,39 +225,35 @@ 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 to kill connection, 0 to continue negotiation */
+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 an NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
+ * Return -errno to kill connection, 0 to continue negotiation */
static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
{
- uint64_t magic, name_len;
- uint32_t opt, type, len;
+ uint32_t len;
+ int rc;
TRACE("Advertising export name '%s'", exp->name ? exp->name : "");
- name_len = strlen(exp->name);
- 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 + sizeof(len));
- if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
- LOG("write failed (length)");
- return -EINVAL;
- }
- len = cpu_to_be32(name_len);
+ len = strlen(exp->name);
+ rc = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST,
+ len + sizeof(len));
+ if (rc < 0) {
+ return rc;
+ }
+
+ len = cpu_to_be32(len);
if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
- LOG("write failed (length)");
+ LOG("write failed (name length)");
return -EINVAL;
}
- if (nbd_negotiate_write(ioc, exp->name, name_len) != name_len) {
+ len = be32_to_cpu(len);
+ if (nbd_negotiate_write(ioc, exp->name, len) != len) {
LOG("write failed (buffer)");
return -EINVAL;
}
--
2.5.5
