Allow OVS_USERSPACE_ATTR_USERDATA to be variable length.

Until now, the optional OVS_USERSPACE_ATTR_USERDATA attribute had to be
exactly 64 bits long, if it was present.  However, 64 bits is not enough
space to associate as much information with a flow as would be convenient
for some userspace features now under development.  This commit generalizes
the attribute, allowing it to be any length.

This generalization is backward-compatible: if userspace only uses 64-bit
attributes, then it will not see any change in behavior.

CC: Romain Lenglet <rlenglet@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>

1 files changed, 43 insertions, 31 deletions

diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index d315b594..305e196b 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -151,7 +151,7 @@ static int dpif_netdev_open(const struct dpif_class *, const char *name,
                             bool create, struct dpif **);
 static int dp_netdev_output_userspace(struct dp_netdev *, const struct ofpbuf *,
                                     int queue_no, const struct flow *,
-                                    uint64_t arg);
+                                    const struct nlattr *userdata);
 static void dp_netdev_execute_actions(struct dp_netdev *,
                                       struct ofpbuf *, struct flow *,
                                       const struct nlattr *actions,
@@ -1043,7 +1043,7 @@ dp_netdev_port_input(struct dp_netdev *dp, struct dp_netdev_port *port,
         dp->n_hit++;
     } else {
         dp->n_missed++;
-        dp_netdev_output_userspace(dp, packet, DPIF_UC_MISS, &key, 0);
+        dp_netdev_output_userspace(dp, packet, DPIF_UC_MISS, &key, NULL);
     }
 }
 
@@ -1108,37 +1108,51 @@ dp_netdev_output_port(struct dp_netdev *dp, struct ofpbuf *packet,
 
 static int
 dp_netdev_output_userspace(struct dp_netdev *dp, const struct ofpbuf *packet,
-                         int queue_no, const struct flow *flow, uint64_t arg)
+                           int queue_no, const struct flow *flow,
+                           const struct nlattr *userdata)
 {
     struct dp_netdev_queue *q = &dp->queues[queue_no];
-    struct dp_netdev_upcall *u;
-    struct dpif_upcall *upcall;
-    struct ofpbuf *buf;
-    size_t key_len;
-
-    if (q->head - q->tail >= MAX_QUEUE_LEN) {
-        dp->n_lost++;
-        return ENOBUFS;
-    }
+    if (q->head - q->tail < MAX_QUEUE_LEN) {
+        struct dp_netdev_upcall *u = &q->upcalls[q->head++ & QUEUE_MASK];
+        struct dpif_upcall *upcall = &u->upcall;
+        struct ofpbuf *buf = &u->buf;
+        size_t buf_size;
+
+        upcall->type = queue_no;
+
+        /* Allocate buffer big enough for everything. */
+        buf_size = ODPUTIL_FLOW_KEY_BYTES + 2 + packet->size;
+        if (userdata) {
+            buf_size += NLA_ALIGN(userdata->nla_len);
+        }
+        ofpbuf_init(buf, buf_size);
 
-    u = &q->upcalls[q->head++ & QUEUE_MASK];
+        /* Put ODP flow. */
+        odp_flow_key_from_flow(buf, flow, flow->in_port);
+        upcall->key = buf->data;
+        upcall->key_len = buf->size;
 
-    buf = &u->buf;
-    ofpbuf_init(buf, ODPUTIL_FLOW_KEY_BYTES + 2 + packet->size);
-    odp_flow_key_from_flow(buf, flow, flow->in_port);
-    key_len = buf->size;
-    ofpbuf_pull(buf, key_len);
-    ofpbuf_reserve(buf, 2);
-    ofpbuf_put(buf, packet->data, packet->size);
+        /* Put userdata. */
+        if (userdata) {
+            upcall->userdata = ofpbuf_put(buf, userdata,
+                                          NLA_ALIGN(userdata->nla_len));
+        }
 
-    upcall = &u->upcall;
-    upcall->type = queue_no;
-    upcall->packet = buf;
-    upcall->key = buf->base;
-    upcall->key_len = key_len;
-    upcall->userdata = arg;
+        /* Put packet.
+         *
+         * We adjust 'data' and 'size' in 'buf' so that only the packet itself
+         * is visible in 'upcall->packet'.  The ODP flow and (if present)
+         * userdata become part of the headroom. */
+        ofpbuf_put_zeros(buf, 2);
+        buf->data = ofpbuf_put(buf, packet->data, packet->size);
+        buf->size = packet->size;
+        upcall->packet = buf;
 
-    return 0;
+        return 0;
+    } else {
+        dp->n_lost++;
+        return ENOBUFS;
+    }
 }
 
 static void
@@ -1180,11 +1194,9 @@ dp_netdev_action_userspace(struct dp_netdev *dp,
                           struct ofpbuf *packet, struct flow *key,
                           const struct nlattr *a)
 {
-    const struct nlattr *userdata_attr;
-    uint64_t userdata;
+    const struct nlattr *userdata;
 
-    userdata_attr = nl_attr_find_nested(a, OVS_USERSPACE_ATTR_USERDATA);
-    userdata = userdata_attr ? nl_attr_get_u64(userdata_attr) : 0;
+    userdata = nl_attr_find_nested(a, OVS_USERSPACE_ATTR_USERDATA);
     dp_netdev_output_userspace(dp, packet, DPIF_UC_ACTION, key, userdata);
 }