[ovs-dev] [of1.5 v2 01/20] ovs-ofctl: Fix port lookup and "ovs-ofctl" behavior for OpenFlow 1.3+.

Ben Pfaff blp at nicira.com
Sat May 10 02:40:17 UTC 2014


ovs-ofctl supports using port names in commands that operate on ports.  It
does this by connecting to the switch, listing the ports, and picking out
the one with the specified name.  However, this didn't work properly for
OpenFlow 1.3+, because it always used an OFPT_FEATURES_REQUEST to list the
ports, and in OpenFlow 1.3+ the reply to this request does not include a
list of ports.  This commit fixes the problem (using code that previously
was just a fallback when there were too many ports to fit in an
OFPT_FEATURES_REPLY).

For similar reasons, "ovs-ofctl show" wasn't listing the switch's ports
when it connected to a switch over OpenFlow 1.3 or later.  This commit
fixes that bug also.

Signed-off-by: Ben Pfaff <blp at nicira.com>

Conflicts:
	utilities/ovs-ofctl.c
---
 lib/ofp-util.c        | 34 ++++++++++---------
 lib/ofp-util.h        |  2 +-
 utilities/ovs-ofctl.c | 93 ++++++++++++++++++++++++++++-----------------------
 3 files changed, 72 insertions(+), 57 deletions(-)

diff --git a/lib/ofp-util.c b/lib/ofp-util.c
index 2106fd8..f2c1c65 100644
--- a/lib/ofp-util.c
+++ b/lib/ofp-util.c
@@ -3935,28 +3935,32 @@ max_ports_in_features(const struct ofp_header *oh)
     return ntohs(oh->length) + pp_size > UINT16_MAX;
 }
 
-/* Given a buffer 'b' that contains a Features Reply message, checks if
- * it contains the maximum number of ports that will fit.  If so, it
- * returns true and removes the ports from the message.  The caller
- * should then send an OFPST_PORT_DESC stats request to get the ports,
- * since the switch may have more ports than could be represented in the
- * Features Reply.  Otherwise, returns false.
- */
+/* In OpenFlow 1.0, 1.1, and 1.2, an OFPT_FEATURES_REPLY message lists all the
+ * switch's ports, unless there are too many to fit.  In OpenFlow 1.3 and
+ * later, an OFPT_FEATURES_REPLY does not list ports at all.
+ *
+ * Given a buffer 'b' that contains a Features Reply message, this message
+ * checks if it contains a complete list of the switch's ports.  Returns true,
+ * if so.  Returns false if the list is missing (OF1.3+) or incomplete
+ * (OF1.0/1.1/1.2), and in the latter case removes all of the ports from the
+ * message.
+ *
+ * When this function returns false, the caller should send an OFPST_PORT_DESC
+ * stats request to get the ports. */
 bool
-ofputil_switch_features_ports_trunc(struct ofpbuf *b)
+ofputil_switch_features_has_ports(struct ofpbuf *b)
 {
     struct ofp_header *oh = ofpbuf_data(b);
 
-    if (max_ports_in_features(oh)) {
-        /* Remove all the ports. */
-        ofpbuf_set_size(b, (sizeof(struct ofp_header) +
-                            sizeof(struct ofp_switch_features)));
+    if (oh->version >= OFP13_VERSION) {
+        return false;
+    } else if (max_ports_in_features(oh)) {
+        ofpbuf_set_size(b, sizeof *oh + sizeof(struct ofp_switch_features));
         ofpmsg_update_length(b);
-
+        return false;
+    } else {
         return true;
     }
-
-    return false;
 }
 
 static ovs_be32
diff --git a/lib/ofp-util.h b/lib/ofp-util.h
index 782e512..9c87cf6 100644
--- a/lib/ofp-util.h
+++ b/lib/ofp-util.h
@@ -569,7 +569,7 @@ struct ofpbuf *ofputil_encode_switch_features(
     ovs_be32 xid);
 void ofputil_put_switch_features_port(const struct ofputil_phy_port *,
                                       struct ofpbuf *);
-bool ofputil_switch_features_ports_trunc(struct ofpbuf *b);
+bool ofputil_switch_features_has_ports(struct ofpbuf *b);
 
 /* phy_port helper functions. */
 int ofputil_pull_phy_port(enum ofp_version ofp_version, struct ofpbuf *,
diff --git a/utilities/ovs-ofctl.c b/utilities/ovs-ofctl.c
index deba9dd..2a0a6b3 100644
--- a/utilities/ovs-ofctl.c
+++ b/utilities/ovs-ofctl.c
@@ -632,27 +632,24 @@ static void
 ofctl_show(int argc OVS_UNUSED, char *argv[])
 {
     const char *vconn_name = argv[1];
+    enum ofp_version version;
     struct vconn *vconn;
     struct ofpbuf *request;
     struct ofpbuf *reply;
-    bool trunc;
+    bool has_ports;
 
     open_vconn(vconn_name, &vconn);
-    request = ofpraw_alloc(OFPRAW_OFPT_FEATURES_REQUEST,
-                           vconn_get_version(vconn), 0);
+    version = vconn_get_version(vconn);
+    request = ofpraw_alloc(OFPRAW_OFPT_FEATURES_REQUEST, version, 0);
     run(vconn_transact(vconn, request, &reply), "talking to %s", vconn_name);
 
-    trunc = ofputil_switch_features_ports_trunc(reply);
+    has_ports = ofputil_switch_features_has_ports(reply);
     ofp_print(stdout, ofpbuf_data(reply), ofpbuf_size(reply), verbosity + 1);
-
     ofpbuf_delete(reply);
 
-    if (trunc) {
-        /* The Features Reply may not contain all the ports, so send a
-         * Port Description stats request, which doesn't have size
-         * constraints. */
-        dump_trivial_stats_transaction(vconn_name,
-                                       OFPRAW_OFPST_PORT_DESC_REQUEST);
+    if (!has_ports) {
+        request = ofpraw_alloc(OFPRAW_OFPST_PORT_DESC_REQUEST, version, 0);
+        dump_stats_transaction(vconn, request);
     }
     dump_trivial_transaction(vconn_name, OFPRAW_OFPT_GET_CONFIG_REQUEST);
     vconn_close(vconn);
@@ -685,43 +682,53 @@ ofctl_dump_table_features(int argc OVS_UNUSED, char *argv[])
     vconn_close(vconn);
 }
 
+static bool fetch_port_by_stats(struct vconn *,
+                                const char *port_name, ofp_port_t port_no,
+                                struct ofputil_phy_port *);
+
+/* Uses OFPT_FEATURES_REQUEST to attempt to fetch information about the port
+ * named 'port_name' or numbered 'port_no' into '*pp'.  Returns true if
+ * successful, false on failure.
+ *
+ * This is only appropriate for OpenFlow 1.0, 1.1, and 1.2, which include a
+ * list of ports in OFPT_FEATURES_REPLY. */
 static bool
-fetch_port_by_features(const char *vconn_name,
+fetch_port_by_features(struct vconn *vconn,
                        const char *port_name, ofp_port_t port_no,
-                       struct ofputil_phy_port *pp, bool *trunc)
+                       struct ofputil_phy_port *pp)
 {
     struct ofputil_switch_features features;
     const struct ofp_header *oh;
     struct ofpbuf *request, *reply;
-    struct vconn *vconn;
     enum ofperr error;
     enum ofptype type;
     struct ofpbuf b;
     bool found = false;
 
     /* Fetch the switch's ofp_switch_features. */
-    open_vconn(vconn_name, &vconn);
     request = ofpraw_alloc(OFPRAW_OFPT_FEATURES_REQUEST,
                            vconn_get_version(vconn), 0);
-    run(vconn_transact(vconn, request, &reply), "talking to %s", vconn_name);
-    vconn_close(vconn);
+    run(vconn_transact(vconn, request, &reply),
+        "talking to %s", vconn_get_name(vconn));
 
     oh = ofpbuf_data(reply);
     if (ofptype_decode(&type, ofpbuf_data(reply))
         || type != OFPTYPE_FEATURES_REPLY) {
-        ovs_fatal(0, "%s: received bad features reply", vconn_name);
+        ovs_fatal(0, "%s: received bad features reply", vconn_get_name(vconn));
     }
-
-    *trunc = false;
-    if (ofputil_switch_features_ports_trunc(reply)) {
-        *trunc = true;
-        goto exit;
+    if (!ofputil_switch_features_has_ports(reply)) {
+        /* The switch features reply does not contain a complete list of ports.
+         * Probably, there are more ports than will fit into a single 64 kB
+         * OpenFlow message.  Use OFPST_PORT_DESC to get a complete list of
+         * ports. */
+        ofpbuf_delete(reply);
+        return fetch_port_by_stats(vconn, port_name, port_no, pp);
     }
 
     error = ofputil_decode_switch_features(oh, &features, &b);
     if (error) {
         ovs_fatal(0, "%s: failed to decode features reply (%s)",
-                  vconn_name, ofperr_to_string(error));
+                  vconn_get_name(vconn), ofperr_to_string(error));
     }
 
     while (!ofputil_pull_phy_port(oh->version, &b, pp)) {
@@ -729,30 +736,35 @@ fetch_port_by_features(const char *vconn_name,
             ? port_no == pp->port_no
             : !strcmp(pp->name, port_name)) {
             found = true;
-            goto exit;
+            break;
         }
     }
-
-exit:
     ofpbuf_delete(reply);
     return found;
 }
 
+/* Uses a OFPST_PORT_DESC request to attempt to fetch information about the
+ * port named 'port_name' or numbered 'port_no' into '*pp'.  Returns true if
+ * successful, false on failure.
+ *
+ * This is most appropriate for OpenFlow 1.3 and later.  Open vSwitch 1.7 and
+ * later also implements OFPST_PORT_DESC, as an extension, for OpenFlow 1.0,
+ * 1.1, and 1.2, so this can be used as a fallback in those versions when there
+ * are too many ports than fit in an OFPT_FEATURES_REPLY. */
 static bool
-fetch_port_by_stats(const char *vconn_name,
+fetch_port_by_stats(struct vconn *vconn,
                     const char *port_name, ofp_port_t port_no,
                     struct ofputil_phy_port *pp)
 {
     struct ofpbuf *request;
-    struct vconn *vconn;
     ovs_be32 send_xid;
     bool done = false;
     bool found = false;
 
-    request = ofpraw_alloc(OFPRAW_OFPST_PORT_DESC_REQUEST, OFP10_VERSION, 0);
+    request = ofpraw_alloc(OFPRAW_OFPST_PORT_DESC_REQUEST,
+                           vconn_get_version(vconn), 0);
     send_xid = ((struct ofp_header *) ofpbuf_data(request))->xid;
 
-    open_vconn(vconn_name, &vconn);
     send_openflow_buffer(vconn, request);
     while (!done) {
         ovs_be32 recv_xid;
@@ -796,7 +808,6 @@ fetch_port_by_stats(const char *vconn_name,
         }
         ofpbuf_delete(reply);
     }
-    vconn_close(vconn);
 
     return found;
 }
@@ -819,23 +830,23 @@ static void
 fetch_ofputil_phy_port(const char *vconn_name, const char *port_name,
                        struct ofputil_phy_port *pp)
 {
+    struct vconn *vconn;
     ofp_port_t port_no;
     bool found;
-    bool trunc;
 
     /* Try to interpret the argument as a port number. */
     if (!str_to_ofp(port_name, &port_no)) {
         port_no = OFPP_NONE;
     }
 
-    /* Try to find the port based on the Features Reply.  If it looks
-     * like the results may be truncated, then use the Port Description
-     * stats message introduced in OVS 1.7. */
-    found = fetch_port_by_features(vconn_name, port_name, port_no, pp,
-                                   &trunc);
-    if (trunc) {
-        found = fetch_port_by_stats(vconn_name, port_name, port_no, pp);
-    }
+    /* OpenFlow 1.0, 1.1, and 1.2 put the list of ports in the
+     * OFPT_FEATURES_REPLY message.  OpenFlow 1.3 and later versions put it
+     * into the OFPST_PORT_DESC reply.  Try it the correct way. */
+    open_vconn(vconn_name, &vconn);
+    found = (vconn_get_version(vconn) < OFP13_VERSION
+             ? fetch_port_by_features(vconn, port_name, port_no, pp)
+             : fetch_port_by_stats(vconn, port_name, port_no, pp));
+    vconn_close(vconn);
 
     if (!found) {
         ovs_fatal(0, "%s: couldn't find port `%s'", vconn_name, port_name);
-- 
1.9.1




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