netdev-dpdk: add DPDK pdump capability

This commit provides the ability to 'listen' on DPDK ports and save
packets to a pcap file with a DPDK app that uses the librte_pdump
library. One such app is the 'pdump' app that can be found in the DPDK
'app' directory. Instructions on how to use this can be found in
INSTALL.DPDK-ADVANCED.md

Pdump capability in OVS with DPDK will only be initialised if the
CONFIG_RTE_LIBRTE_PMD_PCAP=y and CONFIG_RTE_LIBRTE_PDUMP=y options are
set in DPDK. libpcap is required if the above configuration is used.

Signed-off-by: Ciara Loftus <[email protected]>
Signed-off-by: Daniele Di Proietto <[email protected]>

INSTALL.DPDK-ADVANCED.md

@@ -12,7 +12,8 @@ OVS DPDK ADVANCED INSTALL GUIDE
 7. [QOS](#qos)
 8. [Rate Limiting](#rl)
 9. [Flow Control](#fc)
-10. [Vsperf](#vsperf)
+10. [Pdump](#pdump)
+11. [Vsperf](#vsperf)
 
 ## <a name="overview"></a> 1. Overview
 
@@ -947,7 +948,40 @@ respective parameter. To disable the flow control at tx side,
 
 `ovs-vsctl set Interface dpdk0 options:tx-flow-ctrl=false`
 
-## <a name="vsperf"></a> 10. Vsperf
+## <a name="pdump"></a> 10. Pdump
+
+Pdump allows you to listen on DPDK ports and view the traffic that is
+passing on them. To use this utility, one must have libpcap installed
+on the system. Furthermore, DPDK must be built with CONFIG_RTE_LIBRTE_PDUMP=y
+and CONFIG_RTE_LIBRTE_PMD_PCAP=y.
+
+To use pdump, simply launch OVS as usual. Then, navigate to the 'app/pdump'
+directory in DPDK, 'make' the application and run like so:
+
+```
+sudo ./build/app/dpdk_pdump --
+--pdump port=0,queue=0,rx-dev=/tmp/pkts.pcap
+--server-socket-path=/usr/local/var/run/openvswitch
+```
+
+The above command captures traffic received on queue 0 of port 0 and stores
+it in /tmp/pkts.pcap. Other combinations of port numbers, queues numbers and
+pcap locations are of course also available to use. 'server-socket-path' must
+be set to the value of ovs_rundir() which typically resolves to
+'/usr/local/var/run/openvswitch'.
+More information on the pdump app and its usage can be found in the below link.
+
+http://dpdk.org/doc/guides/sample_app_ug/pdump.html
+
+Many tools are available to view the contents of the pcap file. Once example is
+tcpdump. Issue the following command to view the contents of 'pkts.pcap':
+
+`tcpdump -r pkts.pcap`
+
+A performance decrease is expected when using a monitoring application like
+the DPDK pdump app.
+
+## <a name="vsperf"></a> 11. Vsperf
 
 Vsperf project goal is to develop vSwitch test framework that can be used to
 validate the suitability of different vSwitch implementations in a Telco deployment

NEWS

@@ -69,6 +69,7 @@ Post-v2.5.0
      * Basic connection tracking for the userspace datapath (no ALG,
        fragmentation or NAT support yet)
      * Support for DPDK 16.07
+     * Optional support for DPDK pdump enabled.
    - Increase number of registers to 16.
    - ovs-benchmark: This utility has been removed due to lack of use and
      bitrot.

acinclude.m4

@@ -221,6 +221,29 @@ AC_DEFUN([OVS_CHECK_DPDK], [
       [AC_SEARCH_LIBS([get_mempolicy],[numa],[],[AC_MSG_ERROR([unable to find libnuma, install the dependency package])])
        DPDK_EXTRA_LIB="-lnuma"])
 
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM(
+        [
+          #include <rte_config.h>
+#if RTE_LIBRTE_PMD_PCAP
+#error
+#endif
+        ], [])
+      ], [],
+      [AC_SEARCH_LIBS([pcap_dump],[pcap],[],[AC_MSG_ERROR([unable to find libpcap, install the dependency package])])
+       DPDK_EXTRA_LIB="-lpcap"
+       AC_COMPILE_IFELSE([
+         AC_LANG_PROGRAM(
+           [
+             #include <rte_config.h>
+#if RTE_LIBRTE_PDUMP
+#error
+#endif
+         ], [])
+       ], [],
+       [AC_DEFINE([DPDK_PDUMP], [1], [DPDK pdump enabled in OVS.])])
+     ])
+
     # On some systems we have to add -ldl to link with dpdk
     #
     # This code, at first, tries to link without -ldl (""),

lib/netdev-dpdk.c

@@ -57,6 +57,9 @@
 #include "rte_config.h"
 #include "rte_mbuf.h"
 #include "rte_meter.h"
+#ifdef DPDK_PDUMP
+#include "rte_pdump.h"
+#endif
 #include "rte_virtio_net.h"
 
 VLOG_DEFINE_THIS_MODULE(dpdk);
@@ -3412,6 +3415,22 @@ dpdk_init__(const struct smap *ovs_other_config)
 
     dpdk_vhost_class_init();
 
+#ifdef DPDK_PDUMP
+    VLOG_INFO("DPDK pdump packet capture enabled");
+    err = rte_pdump_init(ovs_rundir());
+    if (err) {
+        VLOG_INFO("Error initialising DPDK pdump");
+        rte_pdump_uninit();
+    } else {
+        char *server_socket_path;
+
+        server_socket_path = xasprintf("%s/%s", ovs_rundir(),
+                                       "pdump_server_socket");
+        fatal_signal_add_file_to_unlink(server_socket_path);
+        free(server_socket_path);
+    }
+#endif
+
     /* Finally, register the dpdk classes */
     netdev_dpdk_register();
 }