transport: Add blocking recv calls to uhd-dpdk

This adds an internal wait queue API to uhd-dpdk. Socket configuration
requests had their blocking calls re-implemented on top of this API, and
it is also used to service requests to wait on RX packets (w/ timeout).

The wait API involves a multi-producer, single-consumer queue per I/O
thread (waiter_ring), with a condition variable used for sleeping. The
data structure is shared between user thread and I/O thread, and because
timeouts make resource release time non-deterministic, we use reference
counting on the shared resource.

One reference is generated by the user thread and passed to the I/O
thread to consume. A user thread that still needs the data after waking
must get() another reference, to postpone the destruction of the
resource until it is done.

Timeouts are based on CLOCK_MONOTONIC. For recv, a timeout of 0
indicates blocking indefinitely, and a negative timeout indicates no
timeout is desired.

Also drop timeout for closing sockets in uhd-dpdk.
The timeout would allow a user thread to pre-empt the I/O thread's
cleanup process. The user thread would free data structures the I/O
thread still needed to function. Since this timeout is superfluous
anyway, let's just get rid of it.

Also add some more input checking and error reporting.

1 files changed, 8 insertions, 0 deletions

diff --git a/host/lib/transport/uhd-dpdk/uhd_dpdk_fops.h b/host/lib/transport/uhd-dpdk/uhd_dpdk_fops.h
index c07c1913a..66adb0f54 100644
--- a/host/lib/transport/uhd-dpdk/uhd_dpdk_fops.h
+++ b/host/lib/transport/uhd-dpdk/uhd_dpdk_fops.h
@@ -12,4 +12,12 @@ int _uhd_dpdk_config_req_compl(struct uhd_dpdk_config_req *req, int retval);
 
 int _uhd_dpdk_sock_setup(struct uhd_dpdk_config_req *req);
 int _uhd_dpdk_sock_release(struct uhd_dpdk_config_req *req);
+
+/*
+ * Get key for RX table corresponding to this socket
+ *
+ * This is primarily used to get access to the waiter entry
+ */
+int _uhd_dpdk_sock_rx_key(struct uhd_dpdk_socket *sock,
+                          struct uhd_dpdk_ipv4_5tuple *key);
 #endif /* _UHD_DPDK_FOPS_H_ */