uhd-dpdk: Add DPDK-based sockets-like library

This library makes available a userspace network stack with a
socket-like interface for applications (except the sockets pass around
pointers to buffers and use the buffers directly--It's sockets + a
put/get for buffer management). Supported services are ARP and UDP.
Destinations can be unicast or broadcast. Multicast is not currently
supported.

The implementation has two driver layers. The upper layer runs within
the caller's context. The caller will make requests through lockless
ring buffers (including socket creation and packet transmission), and
the lower layer will implement the requests and provide a response.

Currently, the lower layer runs in a separate I/O thread, and the caller
will block until it receives a response.

The I/O thread's main body is in src/uhd_dpdk_driver.c. You'll find that
all I/O thread functions are prefixed by an underscore, and user thread
functions do not.

src/uhd_dpdk.c is used to initialize uhd-dpdk and bring up the network
interfaces.

src/uhd_dpdk_fops.c and src/uhd_dpdk_udp.c are for network services.

The test is a benchmark of a flow control loop using a certain made-up
protocol with credits and sequence number tracking.

1 files changed, 30 insertions, 0 deletions

diff --git a/host/lib/transport/uhd-dpdk/uhd_dpdk_udp.h b/host/lib/transport/uhd-dpdk/uhd_dpdk_udp.h
new file mode 100644
index 000000000..651ae144e
--- /dev/null
+++ b/host/lib/transport/uhd-dpdk/uhd_dpdk_udp.h
@@ -0,0 +1,30 @@
+//
+// Copyright 2018 Ettus Research, a National Instruments Company
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+#ifndef _UHD_DPDK_UDP_H_
+#define _UHD_DPDK_UDP_H_
+
+#include "uhd_dpdk_ctx.h"
+#include <rte_udp.h>
+
+struct uhd_dpdk_udp_priv {
+    uint16_t src_port;
+    uint16_t dst_port;
+    uint32_t dst_ipv4_addr;
+    uint32_t dropped_pkts;
+    /* TODO: Cache destination address ptr to avoid ARP table lookup cost? */
+    //struct uhd_dpdk_arp_entry *arp_entry;
+};
+
+int _uhd_dpdk_udp_setup(struct uhd_dpdk_config_req *req);
+int _uhd_dpdk_udp_release(struct uhd_dpdk_config_req *req);
+
+void uhd_dpdk_udp_open(struct uhd_dpdk_config_req *req,
+                       struct uhd_dpdk_sockarg_udp *arg);
+void uhd_dpdk_udp_close(struct uhd_dpdk_config_req *req);
+
+int uhd_dpdk_udp_prep(struct uhd_dpdk_socket *sock,
+                      struct rte_mbuf *mbuf);
+#endif /* _UHD_DPDK_UDP_H_ */