[openib-general] [RFC/PATCH] librdmacm: use the ipoib broadcast group qkey

[Or Gerlitz]

Sean,

Using the two patches udaddy works fine except for the packets sent by
the passive side which are filtered out by the active side HCA/QP.

This is b/c the passive side of this --test-- is not really doing
RDMA CM UD qp and qkey resolution but rather uses the imm data to
"exchange" (below) the active side qp and hard coded qkey. I think that
in real life librdmacm apps this sort of design is much less expected, and
the passive side would also initiate qp/qkey/sidr exchange.

I need to think on this point a little bit to see if my design can be
changed a little to allow for this sort of simplification.

+/*
+ * Global qkey value for all UD QPs and multicast groups created via the
+ * RDMA CM.
+ * XXX FIXME - enhance test to not assume a pre defined qkey
+ */
+#define RDMA_UD_QKEY 0x01234567
+
+static void create_reply_ah(struct cmatest_node *node, struct ibv_wc *wc)
+{
+	node->ah = ibv_create_ah_from_wc(node->pd, wc, node->mem,
+					 node->cma_id->port_num);
+	node->remote_qpn = ntohl(wc->imm_data);
+	node->remote_qkey = RDMA_UD_QKEY;
+}

Or.