net/null: add argument for no Rx

Add an new device argument 'no-rx', which will prevent PMD receiving
packets.

This is useful for testing when a PMD is needed only to send packets to.

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>

diff --git a/doc/guides/nics/null.rst b/doc/guides/nics/null.rst
index 405edf0..c68d0d6 100644 (file)
--- a/doc/guides/nics/null.rst
+++ b/doc/guides/nics/null.rst
@@ -37,3 +37,7 @@ Runtime Config Options
 
    $RTE_TARGET/app/testpmd -l 0-3 -n 4 --vdev "net_null0,size=256" -- -i
 
+- ``no-rx`` [optional, default disabled]
+
+ Makes PMD more like ``/dev/null``. On Rx no packets received, on Tx all packets are freed.
+ This option can't co-exist with ``copy`` option.

diff --git a/drivers/net/null/rte_eth_null.c b/drivers/net/null/rte_eth_null.c
index 2c08ebf..11258cc 100644 (file)
--- a/drivers/net/null/rte_eth_null.c
+++ b/drivers/net/null/rte_eth_null.c
@@ -14,13 +14,16 @@
 
 #define ETH_NULL_PACKET_SIZE_ARG       "size"
 #define ETH_NULL_PACKET_COPY_ARG       "copy"
+#define ETH_NULL_PACKET_NO_RX_ARG      "no-rx"
 
 static unsigned int default_packet_size = 64;
 static unsigned int default_packet_copy;
+static unsigned int default_no_rx;
 
 static const char *valid_arguments[] = {
        ETH_NULL_PACKET_SIZE_ARG,
        ETH_NULL_PACKET_COPY_ARG,
+       ETH_NULL_PACKET_NO_RX_ARG,
        NULL
 };
 
@@ -39,11 +42,13 @@ struct null_queue {
 struct pmd_options {
        unsigned int packet_copy;
        unsigned int packet_size;
+       unsigned int no_rx;
 };
 
 struct pmd_internals {
        unsigned int packet_size;
        unsigned int packet_copy;
+       unsigned int no_rx;
        uint16_t port_id;
 
        struct null_queue rx_null_queues[RTE_MAX_QUEUES_PER_PORT];
@@ -126,6 +131,13 @@ eth_null_copy_rx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
        return i;
 }
 
+static uint16_t
+eth_null_no_rx(void *q __rte_unused, struct rte_mbuf **bufs __rte_unused,
+               uint16_t nb_bufs __rte_unused)
+{
+       return 0;
+}
+
 static uint16_t
 eth_null_tx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
 {
@@ -504,6 +516,7 @@ eth_dev_null_create(struct rte_vdev_device *dev, struct pmd_options *args)
        internals = eth_dev->data->dev_private;
        internals->packet_size = args->packet_size;
        internals->packet_copy = args->packet_copy;
+       internals->no_rx = args->no_rx;
        internals->port_id = eth_dev->data->port_id;
        rte_eth_random_addr(internals->eth_addr.addr_bytes);
 
@@ -526,6 +539,9 @@ eth_dev_null_create(struct rte_vdev_device *dev, struct pmd_options *args)
        if (internals->packet_copy) {
                eth_dev->rx_pkt_burst = eth_null_copy_rx;
                eth_dev->tx_pkt_burst = eth_null_copy_tx;
+       } else if (internals->no_rx) {
+               eth_dev->rx_pkt_burst = eth_null_no_rx;
+               eth_dev->tx_pkt_burst = eth_null_tx;
        } else {
                eth_dev->rx_pkt_burst = eth_null_rx;
                eth_dev->tx_pkt_burst = eth_null_tx;
@@ -569,6 +585,24 @@ get_packet_copy_arg(const char *key __rte_unused,
        return 0;
 }
 
+static int
+get_packet_no_rx_arg(const char *key __rte_unused,
+               const char *value, void *extra_args)
+{
+       const char *a = value;
+       unsigned int no_rx;
+
+       if (value == NULL || extra_args == NULL)
+               return -EINVAL;
+
+       no_rx = (unsigned int)strtoul(a, NULL, 0);
+       if (no_rx != 0 && no_rx != 1)
+               return -1;
+
+       *(unsigned int *)extra_args = no_rx;
+       return 0;
+}
+
 static int
 rte_pmd_null_probe(struct rte_vdev_device *dev)
 {
@@ -576,6 +610,7 @@ rte_pmd_null_probe(struct rte_vdev_device *dev)
        struct pmd_options args = {
                .packet_copy = default_packet_copy,
                .packet_size = default_packet_size,
+               .no_rx = default_no_rx,
        };
        struct rte_kvargs *kvlist = NULL;
        struct rte_eth_dev *eth_dev;
@@ -602,6 +637,9 @@ rte_pmd_null_probe(struct rte_vdev_device *dev)
                if (internals->packet_copy) {
                        eth_dev->rx_pkt_burst = eth_null_copy_rx;
                        eth_dev->tx_pkt_burst = eth_null_copy_tx;
+               } else if (internals->no_rx) {
+                       eth_dev->rx_pkt_burst = eth_null_no_rx;
+                       eth_dev->tx_pkt_burst = eth_null_tx;
                } else {
                        eth_dev->rx_pkt_burst = eth_null_rx;
                        eth_dev->tx_pkt_burst = eth_null_tx;
@@ -627,6 +665,20 @@ rte_pmd_null_probe(struct rte_vdev_device *dev)
                                &get_packet_copy_arg, &args.packet_copy);
                if (ret < 0)
                        goto free_kvlist;
+
+               ret = rte_kvargs_process(kvlist,
+                               ETH_NULL_PACKET_NO_RX_ARG,
+                               &get_packet_no_rx_arg, &args.no_rx);
+               if (ret < 0)
+                       goto free_kvlist;
+
+               if (args.no_rx && args.packet_copy) {
+                       PMD_LOG(ERR,
+                               "Both %s and %s arguments at the same time not supported",
+                               ETH_NULL_PACKET_COPY_ARG,
+                               ETH_NULL_PACKET_NO_RX_ARG);
+                       goto free_kvlist;
+               }
        }
 
        PMD_LOG(INFO, "Configure pmd_null: packet size is %d, "
@@ -675,7 +727,8 @@ RTE_PMD_REGISTER_VDEV(net_null, pmd_null_drv);
 RTE_PMD_REGISTER_ALIAS(net_null, eth_null);
 RTE_PMD_REGISTER_PARAM_STRING(net_null,
        "size=<int> "
-       "copy=<int>");
+       "copy=<int> "
+       ETH_NULL_PACKET_NO_RX_ARG "=0|1");
 
 RTE_INIT(eth_null_init_log)
 {