docs: add VPP Container Testbench example and lab

Adding a "VPP container testbench" (pair of Docker containers plus
helper scripts to test Linux and VPP interfaces). Will be part of a
larger set of labs/exercises/tutorials. Putting this baseline setup up
for review first to see if the community sees use/value in it. If so,
additional exercises using the testbench will be added gradually.

Type: improvement
Signed-off-by: Matthew Giassa <mgiassa@cisco.com>
Change-Id: I582310f7355419e907d575f640482ca49cbb282f

1 files changed, 150 insertions, 0 deletions

diff --git a/docs/usecases/vpp_testbench/src/entrypoint_client.sh b/docs/usecases/vpp_testbench/src/entrypoint_client.sh
new file mode 100755
index 00000000000..432c2769730
--- /dev/null
+++ b/docs/usecases/vpp_testbench/src/entrypoint_client.sh
@@ -0,0 +1,150 @@
+#!/bin/bash
+################################################################################
+# @brief:       Launcher/entrypoint script plus helper functions for "client
+#               side" container in the VPP testbench.
+# @author:      Matthew Giassa <mgiassa@cisco.com>
+# @copyright:   (C) Cisco 2021.
+################################################################################
+
+################################################################################
+# Dependencies.
+################################################################################
+# Import common settings for server and client. This is supplied via the
+# Dockerfile build.
+# shellcheck disable=SC1091
+. vpp_testbench_helpers.sh
+
+################################################################################
+# Globals.
+################################################################################
+# VPP instance socket.
+export VPP_SOCK=/run/vpp/vpp.testbench-client.sock
+# Alias for vppctl that uses the correct socket name.
+export VPPCTL="vppctl -s ${VPP_SOCK}"
+# Our "Docker bridge network". Don't change this value.
+export NET_IF_DOCKER="eth0"
+# Name of link associated with our VXLAN.
+export LINK_VXLAN_LINUX="vxlan-vid-${VXLAN_ID_LINUX}"
+
+################################################################################
+# Function definitions.
+################################################################################
+#------------------------------------------------------------------------------#
+# @brief:   Alias for vppctl (knowing which API socket to use).
+function vc()
+{
+    vppctl -s "${VPP_SOCK}" "${@}"
+}
+
+#------------------------------------------------------------------------------#
+# @brief:   Used to initialize/configure the client container once it's up and
+#           running.
+function context_create()
+{
+    set -x
+    echo "Running client. Host: $(hostname)"
+    local mtu
+
+    # Setup VXLAN overlay.
+    ip link add "${LINK_VXLAN_LINUX}" \
+        type vxlan \
+        id "${VXLAN_ID_LINUX}" \
+        dstport "${VXLAN_PORT}" \
+        local "${CLIENT_BRIDGE_IP_DOCKER}" \
+        group "${MC_VXLAN_ADDR_LINUX}" \
+        dev "${NET_IF_DOCKER}" \
+        ttl 1
+    ip link set "${LINK_VXLAN_LINUX}" up
+    ip addr add "${CLIENT_VXLAN_IP_LINUX}/${MASK_VXLAN_LINUX}" dev "${LINK_VXLAN_LINUX}"
+
+    # Get MTU of interface. VXLAN must use a smaller value due to overhead.
+    mtu="$(cat /sys/class/net/${NET_IF_DOCKER}/mtu)"
+
+    # Decrease VXLAN MTU. This should already be handled for us by iproute2, but
+    # just being cautious.
+    ip link set dev "${LINK_VXLAN_LINUX}" mtu "$((mtu - 50))"
+
+    # Bring-up VPP and create tap interfaces and VXLAN tunnel.
+    vpp \
+        unix '{' log /tmp/vpp1.log full-coredump cli-listen ${VPP_SOCK} '}' \
+        api-segment '{' prefix vpp1 '}' \
+        api-trace '{' on '}' \
+        dpdk '{' uio-driver uio_pci_generic no-pci '}'
+
+    # Wait for VPP to come up.
+    while ! ${VPPCTL} show log; do
+        sleep 1
+    done
+
+    # Bring up the memif interface and assign an IP to it.
+    ${VPPCTL} create interface memif id 0 slave
+    sleep 1
+    ${VPPCTL} set int state memif0/0 up
+    ${VPPCTL} set int ip address memif0/0 "${CLIENT_VPP_MEMIF_IP}/${VPP_MEMIF_NM}"
+
+    # Create VPP-controlled tap interface bridged to the memif.
+    ${VPPCTL} create tap id 0 host-if-name vpp-tap-0
+    sleep 1
+    ${VPPCTL} set interface state tap0 up
+    ip addr add "${CLIENT_VPP_TAP_IP_MEMIF}/${VPP_TAP_NM}" dev vpp-tap-0
+    ${VPPCTL} set interface l2 bridge tap0          "${VPP_BRIDGE_DOMAIN_TAP}"
+    ${VPPCTL} set interface l2 bridge memif0/0      "${VPP_BRIDGE_DOMAIN_TAP}"
+}
+
+#------------------------------------------------------------------------------#
+# @brief:   Used to shutdown/cleanup the client container.
+function context_destroy()
+{
+    # OS will reclaim interfaces and resources when container is terminated.
+    :
+}
+
+#------------------------------------------------------------------------------#
+# @brief:   Client worker loop to keep the container alive. Just idles.
+function context_loop()
+{
+    # Sleep indefinitely (to keep container alive for testing).
+    tail -f /dev/null
+}
+
+#------------------------------------------------------------------------------#
+# @brief:   Launches a minimalistic web server via netcat. The Dockerfile
+#           associated with this project is configured to treat the web server
+#           replying with "200 OK" as a sort of simple health probe.
+function health_check_init()
+{
+    while true; do
+        echo -e "HTTP/1.1 200 OK\n\nHOST:$(hostname)\nDATE:$(date)" \
+            | nc -l -p "${DOCKER_HEALTH_PROBE_PORT}" -q 1
+    done
+}
+
+#------------------------------------------------------------------------------#
+# @brief:   Main/default entry point.
+function main()
+{
+    # Make sure we always cleanup.
+    trap context_destroy EXIT
+
+    # Bring up interfaces.
+    context_create
+
+    # Enable health check responder.
+    health_check_init &
+
+    # Enter our worker loop.
+    context_loop
+}
+
+#------------------------------------------------------------------------------#
+# Script is generally intended to be sourced and individual functions called.
+# If just run as a standalone script, assume it's being used as the entrypoint
+# for a Docker container.
+if [ "${BASH_SOURCE[0]}" -ef "$0" ]; then
+    # Being run. Launch main.
+    main "${@}"
+else
+    # Being sourced. Do nothing.
+    :
+fi
+