Introduce ofputil_protocol, to abstract the protocol in use on a connection.

Open vSwitch already handles a few different protocol variations, but it
does so in a nonuniform manner:

  - OpenFlow 1.0 and NXM flow formats are distinguished using the NXFF_*
    constant values from nicira-ext.h.

  - The "flow_mod_table_id" feature setting is maintained in ofproto as
    part of an OpenFlow connection's (ofconn's) state.

There's no way to easily communicate this state among components.  It's
not much of a problem yet, but as more protocol support is added it seems
better to have an abstract, uniform way to represent protocol versions and
variants.  This commit implements that by introducing a new type
"enum ofputil_protocol".  Each ofputil_protocol value represents a variant
of a protocol version.  Each value is a separate bit, so a single enum
can also represent a set of protocols, which is often useful as well.

Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Ben Pfaff <blp@nicira.com>

1 files changed, 16 insertions, 5 deletions

diff --git a/lib/vconn.c b/lib/vconn.c
index 5da50262..93d6388c 100644
--- a/lib/vconn.c
+++ b/lib/vconn.c
@@ -353,6 +353,17 @@ vconn_get_local_port(const struct vconn *vconn)
     return vconn->local_port;
 }
 
+/* Returns the OpenFlow version negotiated with the peer, or -1 if version
+ * negotiation is not yet complete.
+ *
+ * A vconn that has successfully connected (that is, vconn_connect() or
+ * vconn_send() or vconn_recv() has returned 0) always negotiated a version. */
+int
+vconn_get_version(const struct vconn *vconn)
+{
+    return vconn->version;
+}
+
 static void
 vcs_connecting(struct vconn *vconn)
 {
@@ -471,7 +482,7 @@ vconn_connect(struct vconn *vconn)
 {
     enum vconn_state last_state;
 
-    assert(vconn->min_version >= 0);
+    assert(vconn->min_version > 0);
     do {
         last_state = vconn->state;
         switch (vconn->state) {
@@ -538,14 +549,14 @@ do_recv(struct vconn *vconn, struct ofpbuf **msgp)
         }
 
         oh = ofpbuf_at_assert(*msgp, 0, sizeof *oh);
-        if (oh->version != vconn->version
+        if ((oh->version != vconn->version || oh->version == 0)
             && oh->type != OFPT_HELLO
             && oh->type != OFPT_ERROR
             && oh->type != OFPT_ECHO_REQUEST
             && oh->type != OFPT_ECHO_REPLY
             && oh->type != OFPT_VENDOR)
         {
-            if (vconn->version < 0) {
+            if (vconn->version == 0) {
                 VLOG_ERR_RL(&bad_ofmsg_rl,
                             "%s: received OpenFlow message type %"PRIu8" "
                             "before version negotiation complete",
@@ -995,8 +1006,8 @@ vconn_init(struct vconn *vconn, struct vconn_class *class, int connect_status,
                     : !connect_status ? VCS_SEND_HELLO
                     : VCS_DISCONNECTED);
     vconn->error = connect_status;
-    vconn->version = -1;
-    vconn->min_version = -1;
+    vconn->version = 0;
+    vconn->min_version = 0;
     vconn->remote_ip = 0;
     vconn->remote_port = 0;
     vconn->local_ip = 0;