net/pcap: capture only ingress packets from Rx iface

Support rx of in direction packets only
Useful for apps that also tx to eth_pcap ports in order to not see them
echoed back in as rx when out direction is also captured

Example:
In case using rx_iface and sending *single* packet to eth1
it will loop forever as the when it is sent to tx_iface=eth1
it will be captured again on the rx_iface=eth1 and so on
  $RTE_TARGET/app/testpmd l 0-3 -n 4 \
	--vdev 'net_pcap0,rx_iface=eth1,tx_iface=eth1'
  …
  ---------------------- Forward statistics for port 0  ------------
  RX-packets: 758            RX-dropped: 0             RX-total: 758
  TX-packets: 758            TX-dropped: 0             TX-total: 758
  ------------------------------------------------------------------
While if using rx_iface_in it will not be captured on the way out and
be forwarded only once
  $RTE_TARGET/app/testpmd l 0-3 -n 4 \
	--vdev 'net_pcap0,rx_iface_in=eth1,tx_iface=eth1'
  …
  ---------------------- Forward statistics for port 0  ------------
  RX-packets: 1              RX-dropped: 0             RX-total: 1
  TX-packets: 1              TX-dropped: 0             TX-total: 1
  ------------------------------------------------------------------

Signed-off-by: Ido Goshen <ido@cgstowernetworks.com>
Acked-by: Ferruh Yigit <ferruh.yigit@intel.com>

diff --git a/doc/guides/nics/pcap_ring.rst b/doc/guides/nics/pcap_ring.rst
index 7fd063c..879e543 100644 (file)
--- a/doc/guides/nics/pcap_ring.rst
+++ b/doc/guides/nics/pcap_ring.rst
@@ -71,11 +71,19 @@ The different stream types are:
         tx_pcap=/path/to/file.pcap
 
 *   rx_iface: Defines a reception stream based on a network interface name.
-    The driver reads packets coming from the given interface using the Linux kernel driver for that interface.
+    The driver reads packets from the given interface using the Linux kernel driver for that interface.
+    The driver captures both the incoming and outgoing packets on that interface.
     The value is an interface name.
 
         rx_iface=eth0
 
+*   rx_iface_in: Defines a reception stream based on a network interface name.
+    The driver reads packets from the given interface using the Linux kernel driver for that interface.
+    The driver captures only the incoming packets on that interface.
+    The value is an interface name.
+
+        rx_iface_in=eth0
+
 *   tx_iface: Defines a transmission stream based on a network interface name.
     The driver sends packets to the given interface using the Linux kernel driver for that interface.
     The value is an interface name.
@@ -122,6 +130,21 @@ Forward packets through two network interfaces:
     $RTE_TARGET/app/testpmd -l 0-3 -n 4 \
         --vdev 'net_pcap0,iface=eth0' --vdev='net_pcap1;iface=eth1'
 
+Enable 2 tx queues on a network interface:
+
+.. code-block:: console
+
+    $RTE_TARGET/app/testpmd -l 0-3 -n 4 \
+        --vdev 'net_pcap0,rx_iface=eth1,tx_iface=eth1,tx_iface=eth1' \
+        -- --txq 2
+
+Read only incoming packets from a network interface and write them back to the same network interface:
+
+.. code-block:: console
+
+    $RTE_TARGET/app/testpmd -l 0-3 -n 4 \
+        --vdev 'net_pcap0,rx_iface_in=eth1,tx_iface=eth1'
+
 Using libpcap-based PMD with the testpmd Application
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

diff --git a/drivers/net/pcap/rte_eth_pcap.c b/drivers/net/pcap/rte_eth_pcap.c
index 78c54fc..4c4604c 100644 (file)
--- a/drivers/net/pcap/rte_eth_pcap.c
+++ b/drivers/net/pcap/rte_eth_pcap.c
@@ -26,6 +26,7 @@
 #define ETH_PCAP_RX_PCAP_ARG  "rx_pcap"
 #define ETH_PCAP_TX_PCAP_ARG  "tx_pcap"
 #define ETH_PCAP_RX_IFACE_ARG "rx_iface"
+#define ETH_PCAP_RX_IFACE_IN_ARG "rx_iface_in"
 #define ETH_PCAP_TX_IFACE_ARG "tx_iface"
 #define ETH_PCAP_IFACE_ARG    "iface"
 
@@ -83,6 +84,7 @@ static const char *valid_arguments[] = {
        ETH_PCAP_RX_PCAP_ARG,
        ETH_PCAP_TX_PCAP_ARG,
        ETH_PCAP_RX_IFACE_ARG,
+       ETH_PCAP_RX_IFACE_IN_ARG,
        ETH_PCAP_TX_IFACE_ARG,
        ETH_PCAP_IFACE_ARG,
        NULL
@@ -739,6 +741,21 @@ open_rx_tx_iface(const char *key, const char *value, void *extra_args)
        return 0;
 }
 
+static inline int
+set_iface_direction(const char *iface, pcap_t *pcap,
+               pcap_direction_t direction)
+{
+       const char *direction_str = (direction == PCAP_D_IN) ? "IN" : "OUT";
+       if (pcap_setdirection(pcap, direction) < 0) {
+               PMD_LOG(ERR, "Setting %s pcap direction %s failed - %s\n",
+                               iface, direction_str, pcap_geterr(pcap));
+               return -1;
+       }
+       PMD_LOG(INFO, "Setting %s pcap direction %s\n",
+                       iface, direction_str);
+       return 0;
+}
+
 static inline int
 open_iface(const char *key, const char *value, void *extra_args)
 {
@@ -762,7 +779,29 @@ open_iface(const char *key, const char *value, void *extra_args)
 static inline int
 open_rx_iface(const char *key, const char *value, void *extra_args)
 {
-       return open_iface(key, value, extra_args);
+       int ret = open_iface(key, value, extra_args);
+       if (ret < 0)
+               return ret;
+       if (strcmp(key, ETH_PCAP_RX_IFACE_IN_ARG) == 0) {
+               struct pmd_devargs *pmd = extra_args;
+               unsigned int qid = pmd->num_of_queue - 1;
+
+               set_iface_direction(pmd->queue[qid].name,
+                               pmd->queue[qid].pcap,
+                               PCAP_D_IN);
+       }
+
+       return 0;
+}
+
+static inline int
+rx_iface_args_process(const char *key, const char *value, void *extra_args)
+{
+       if (strcmp(key, ETH_PCAP_RX_IFACE_ARG) == 0 ||
+                       strcmp(key, ETH_PCAP_RX_IFACE_IN_ARG) == 0)
+               return open_rx_iface(key, value, extra_args);
+
+       return 0;
 }
 
 /*
@@ -965,12 +1004,13 @@ pmd_pcap_probe(struct rte_vdev_device *dev)
        is_rx_pcap = rte_kvargs_count(kvlist, ETH_PCAP_RX_PCAP_ARG) ? 1 : 0;
        pcaps.num_of_queue = 0;
 
-       if (is_rx_pcap)
+       if (is_rx_pcap) {
                ret = rte_kvargs_process(kvlist, ETH_PCAP_RX_PCAP_ARG,
                                &open_rx_pcap, &pcaps);
-       else
-               ret = rte_kvargs_process(kvlist, ETH_PCAP_RX_IFACE_ARG,
-                               &open_rx_iface, &pcaps);
+       } else {
+               ret = rte_kvargs_process(kvlist, NULL,
+                               &rx_iface_args_process, &pcaps);
+       }
 
        if (ret < 0)
                goto free_kvlist;
@@ -1036,6 +1076,7 @@ RTE_PMD_REGISTER_PARAM_STRING(net_pcap,
        ETH_PCAP_RX_PCAP_ARG "=<string> "
        ETH_PCAP_TX_PCAP_ARG "=<string> "
        ETH_PCAP_RX_IFACE_ARG "=<ifc> "
+       ETH_PCAP_RX_IFACE_IN_ARG "=<ifc> "
        ETH_PCAP_TX_IFACE_ARG "=<ifc> "
        ETH_PCAP_IFACE_ARG "=<ifc>");