Encapsulate the code handles the negotiation phase of establishing a
ceph connection with a peer, and add a bunch of documentation about
what's involved. Change process_connect() to return 1 on success
rather than 0, to allow the new ceph_con_negotiate_response() to
return 0 to indicate the response has not yet been completely read.
Signed-off-by: Alex Elder <elder@xxxxxxxxxxx>
---
net/ceph/messenger.c | 107
+++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 91 insertions(+), 16 deletions(-)
Index: b/net/ceph/messenger.c
===================================================================
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -1633,7 +1633,7 @@ static int process_connect(struct ceph_c
con->error_msg = "protocol error, garbage tag during connect";
return -1;
}
- return 0;
+ return 1;
}
@@ -2023,6 +2023,82 @@ static int ceph_con_connect_response(str
}
/*
+ * The first phase of connecting with the peer succeeded. Now start
+ * the second phase (negotiating), which consists of:
+ * - client sends a connect message to server, specifying
+ * information about itself, including the protocol it intends to
+ * use and the features it supports.
+ * - if authorizer data is needed for the connection, its length is
+ * recorded in the connect message, and client sends its content
+ * immediately after the connect message
+ * - server receives the connect message from the client, and if it
+ * indicates authorizer data follows, reads that also.
+ * If all is well to this point, then we begin processing the
+ * negotiation response.
+ */
+static int ceph_con_negotiate(struct ceph_connection *con)
+{
+ int ret;
+
+ clear_bit(CONNECTING, &con->state);
+ set_bit(NEGOTIATING, &con->state);
+
+ /* Banner was good, exchange connection info */
+ ret = prepare_write_connect(con);
+ if (ret >= 0)
+ prepare_read_connect(con);
+
+ return ret;
+}
+
+/*
+ * Handle the response from the negotiating phase of connecting the
+ * peer. This consists of:
+ * - server validates the connect message (and possibly authorizer
+ * data), and sends a response to the client:
+ * - if the protocol version supplied by the client is not what
+ * was expected, response is a BADPROTOVER tag
+ * - if the features supported by the client are missing
+ * features required by the server, response is a FEATURES
+ * tag.
+ * - if the features supported by the client are missing
+ * - if authorizer data is supplied by the client and it is not
+ * valid, response is a BADAUTHORIZER tag.
+ * - (There are some other conditions related to message and
+ * connection sequence numbers but they are not covered here)
+ * - Otherwise the response will begin with a READY tag, and
+ * will include a ceph connect reply message, which will
+ * include the features supported by the server, and the
+ * server's own authorization data.
+ * - client validates the connect message (and possibly authorizer
+ * data) from the server:
+ * - If the tag indicates a bad protocol or mismatching
+ * features, the connection attempt is abandoned, so the ceph
+ * connection is reset and closed.
+ * - If the tag indicates a bad authorizer, a second connect
+ * attempt is initiated. If a second attempt fails due to a
+ * bad authorizer, the connection attempt fails.
+ * - If the tag indicates READY, the client will check the
+ * features supported by the server. If the server's
+ * features do not include a feature required by the client,
+ * the connection attempt is abandoned, so the ceph
+ * connection is reset and closed.
+ * If no failures occurred to this point, the connection is established.
+ */
+static int ceph_con_negotiate_response(struct ceph_connection *con)
+{
+ int ret;
+
+ dout("%s negotiating\n", __func__);
+
+ ret = read_partial_connect(con);
+ if (ret > 0)
+ ret = process_connect(con);
+
+ return ret;
+}
+
+/*
* Write something to the socket. Called in a worker thread when the
* socket appears to be writeable and we have something ready to send.
*/
@@ -2136,31 +2212,30 @@ more:
}
if (test_bit(CONNECTING, &con->state)) {
+ /*
+ * See if we got the response we expect from our
+ * connection request.
+ */
ret = ceph_con_connect_response(con);
if (ret <= 0)
goto out;
- clear_bit(CONNECTING, &con->state);
- set_bit(NEGOTIATING, &con->state);
-
- /* Banner is good, exchange connection info */
- ret = prepare_write_connect(con);
- if (ret < 0)
- goto out;
- prepare_read_connect(con);
+ /*
+ * All good. Initiate the negotiation phase of the
+ * connection. If this succeeds, we're done reading
+ * and we next need to send the messages we've
+ * queued up. If it fails, we're also done.
+ */
+ ret = ceph_con_negotiate(con);
- /* Send connection info before awaiting response */
- goto out;
+ goto out; /* Regardless of result */
}
if (test_bit(NEGOTIATING, &con->state)) {
- dout("try_read negotiating\n");
- ret = read_partial_connect(con);
+ ret = ceph_con_negotiate_response(con);
if (ret <= 0)
goto out;
- ret = process_connect(con);
- if (ret < 0)
- goto out;
+
goto more;
}
--
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