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, 249 insertions, 0 deletions

diff --git a/host/lib/include/uhd/transport/uhd-dpdk.h b/host/lib/include/uhd/transport/uhd-dpdk.h
new file mode 100644
index 000000000..5f74ee9b4
--- /dev/null
+++ b/host/lib/include/uhd/transport/uhd-dpdk.h
@@ -0,0 +1,249 @@
+//
+// Copyright 2018 Ettus Research, a National Instruments Company
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+#ifndef _UHD_DPDK_H_
+#define _UHD_DPDK_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <rte_mbuf.h>
+
+/* For MAC address */
+struct eth_addr {
+    uint8_t addr[6];
+};
+
+/* Opaque type representing a socket
+ * May NOT be shared between threads
+ */
+struct uhd_dpdk_socket;
+
+/* Only support UDP sockets currently */
+enum uhd_dpdk_sock_type {
+    UHD_DPDK_SOCK_UDP = 0,
+    UHD_DPDK_SOCK_TYPE_COUNT
+};
+
+/**
+ * Init UHD-DPDK environment and bring up ports (link UP).
+ *
+ * Offload capabilities will be used if available
+ * 
+ * @param argc passed directly to rte_eal_init()
+ * @param argv passed directly to rte_eal_init()
+ * @param num_ports number of network interfaces to map
+ * @param port_thread_mapping array of num_ports entries specifying which thread
+ *     will drive the I/O for a given port (determined by array index)
+ * @param num_mbufs number of packets in each packet buffer pool (multiplied by num_ports)
+ *     There is one RX and one TX buffer pool per CPU socket
+ * @param mbuf_cache_size Number of packet buffers to put in core-local cache
+ * @param mtu Maximum frame size
+ *
+ * @return Returns negative error code if there were issues, else 0
+ */
+int uhd_dpdk_init(int argc, char **argv, unsigned int num_ports,
+                  int *port_thread_mapping, int num_mbufs, int mbuf_cache_size,
+                  int mtu);
+
+/**
+ * @return Returns number of ports registered to DPDK.
+ *         Returns negative error value if uhd-dpdk hasn't been init'd
+ */
+int uhd_dpdk_port_count(void);
+
+/**
+ * @return Returns Ethernet MAC address of requested port
+ *
+ * @param portid ID number of network interface
+ */
+struct eth_addr uhd_dpdk_get_eth_addr(unsigned int portid);
+
+/**
+ * Get IPv4 address of requested port
+ *
+ * @param portid ID number of network interface
+ * @param ipv4_addr pointer to uint32_t where ipv4 address is stored
+ *     Must be non-NULL
+ * @param netmask pointer to uint32_t where netmask is stored
+ *     May be left NULL
+ *
+ * @return Returns
+ *  0 = success
+ *  nonzero = failure
+ */
+int uhd_dpdk_get_ipv4_addr(unsigned int portid, uint32_t *ipv4_addr, uint32_t *netmask);
+
+/**
+ * Sets IPv4 address of requested port
+ *
+ * @param portid ID number of network interface
+ * @param ipv4_addr must be in network format
+ * @param netmask must be in network format
+ *
+ * @return Return values:
+ * 0 = success
+ * nonzero = failure
+ */
+int uhd_dpdk_set_ipv4_addr(unsigned int portid, uint32_t ipv4_addr, uint32_t netmask);
+
+/**
+ * Create new socket of type sock_type on port portid
+ * Copies needed info from sockarg
+ * Do NOT share struct uhd_dpdk_socket between threads!
+ *
+ * @param portid ID number of network interface
+ * @param t Type of socket to create (only UDP supported currently)
+ * @param sockarg Pointer to arguments for corresponding socket type
+ *
+ * @return Returns pointer to socket structure on success, else NULL
+ */
+struct uhd_dpdk_socket* uhd_dpdk_sock_open(unsigned int portid,
+                                           enum uhd_dpdk_sock_type t, void *sockarg);
+
+/**
+ * Close socket created by uhd_dpdk_sock_open
+ *
+ * Note: Outstanding packet buffers must still be freed by user
+ *
+ * @param sock Socket to close
+ *
+ * @return Returns
+ *  0 = success
+ *  nonzero = failure
+ */
+int uhd_dpdk_sock_close(struct uhd_dpdk_socket *sock);
+
+/**
+ * Arguments for a UDP socket
+ * All data should be provided in network format
+ */
+struct uhd_dpdk_sockarg_udp {
+    /*! True for TX socket, false for RX socket */
+    bool     is_tx;
+    /*! Local udp port. This is dst_port for RX, src_port for TX */
+    uint16_t local_port;
+    /*! Remote udp port. This is dst_port for TX */
+    uint16_t remote_port;
+    /*! IPv4 address for destination (TX) */
+    uint32_t dst_addr;
+};
+
+/**
+ * Brings all ports and threads down in preparation for a clean program exit
+ *
+ * All sockets will need to be closed by the user for a thread to terminate in
+ * this function.
+ */
+int uhd_dpdk_destroy(void);
+
+/**
+ * Requests num_bufs buffers from sock. Places pointers to buffers in bufs table.
+ *
+ * @param sock pointer to socket
+ * @param bufs pointer to array of buffers (to store buffer locations)
+ * @param num_bufs number of buffers requested
+ *
+ * @return Returns number of buffers retrieved or negative error code
+ */
+int uhd_dpdk_request_tx_bufs(struct uhd_dpdk_socket *sock, struct rte_mbuf **bufs, unsigned int num_bufs);
+
+/**
+ * Enqueues num_bufs buffers in sock TX buffer. Uses pointers to buffers in bufs table.
+ *
+ * @param sock pointer to socket
+ * @param bufs pointer to array of buffers (to retrieve buffer locations)
+ * @param num_bufs number of buffers requested
+ *
+ * @return Returns number of buffers enqueued or negative error code
+ */
+int uhd_dpdk_send(struct uhd_dpdk_socket *sock, struct rte_mbuf **bufs, unsigned int num_bufs);
+
+/**
+ * Dequeues num_bufs buffers from sock RX buffer. Uses pointers to buffers in bufs table.
+ *
+ * @param sock pointer to socket
+ * @param bufs pointer to array of buffers (to store buffer locations)
+ * @param num_bufs number of buffers requested
+ * @param timeout Time (in us) to wait for a packet
+ *
+ * @return Returns number of buffers dequeued or negative error code
+ *
+ * NOTE: MUST free buffers with uhd_dpdk_free_buf once finished
+ */
+int uhd_dpdk_recv(struct uhd_dpdk_socket *sock, struct rte_mbuf **bufs,
+                  unsigned int num_bufs, unsigned int timeout);
+
+/**
+ * Frees buffer previously received from uhd_dpdk_recv
+ *      (or unused ones from uhd_dpdk_request_tx_bufs)
+ *
+ * @param buf pointer to packet buffer
+ */
+void uhd_dpdk_free_buf(struct rte_mbuf *buf);
+
+/**
+ * Returns pointer to start of data segment of packet buffer
+ *
+ * @param sock Socket associated with packet buffer
+ * @param buf pointer to packet buffer
+ */
+void * uhd_dpdk_buf_to_data(struct uhd_dpdk_socket *sock, struct rte_mbuf *buf);
+
+/**
+ * Returns size of data segment of packet buffer (in bytes)
+ *
+ * This is protocol-dependent. A UDP socket will return the UDP payload size.
+ *
+ * @param sock Socket associated with packet buffer
+ * @param buf pointer to packet buffer
+ *
+ * @return Return 0 for success, else failed
+ */
+int uhd_dpdk_get_len(struct uhd_dpdk_socket *sock, struct rte_mbuf *buf);
+
+/**
+ * Get IPv4 address of sender (for UDP RX socket)
+ *
+ * @param sock Socket associated with packet buffer
+ * @param buf pointer to packet buffer
+ * @param ipv4_addr pointer to buffer where ipv4 address will be written
+ *
+ * @return Return 0 for success, else failed
+ */
+int uhd_dpdk_get_src_ipv4(struct uhd_dpdk_socket *sock, struct rte_mbuf *buf,
+                          uint32_t *ipv4_addr);
+
+/**
+ * Get info (local port, remote port, dst addr, etc.) for UDP socket
+ *
+ * @param sock Socket to get information from
+ * @param sockarg Pointer to location where information will be stored
+ *
+ * @return Return 0 for success, else failed
+ */
+int uhd_dpdk_udp_get_info(struct uhd_dpdk_socket *sock, struct uhd_dpdk_sockarg_udp *sockarg);
+
+
+/***********************************************
+ * Statistics
+ ***********************************************/
+/**
+ * Get dropped packet count of provided socket
+ *
+ * @param sock Socket to get information from
+ * @param count Pointer to location where information will be stored
+ *
+ * @return Return 0 for success, else failed
+ */
+int uhd_dpdk_get_drop_count(struct uhd_dpdk_socket *sock, uint32_t *count);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* _UHD_DPDK_H_ */