1 files changed, 258 insertions, 0 deletions
diff --git a/collectors/cgroups.plugin/cgroup-network-helper.sh b/collectors/cgroups.plugin/cgroup-network-helper.sh
new file mode 100755
index 0000000..666f02f
--- /dev/null
+++ b/collectors/cgroups.plugin/cgroup-network-helper.sh
@@ -0,0 +1,258 @@
+#!/usr/bin/env bash
+# shellcheck disable=SC1117
+
+# cgroup-network-helper.sh
+# detect container and virtual machine interfaces
+#
+# (C) 2017 Costa Tsaousis
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# This script is called as root (by cgroup-network), with either a pid, or a cgroup path.
+# It tries to find all the network interfaces that belong to the same cgroup.
+#
+# It supports several method for this detection:
+#
+# 1. cgroup-network (the binary father of this script) detects veth network interfaces,
+#    by examining iflink and ifindex IDs and switching namespaces
+#    (it also detects the interface name as it is used by the container).
+#
+# 2. this script, uses /proc/PID/fdinfo to find tun/tap network interfaces.
+#
+# 3. this script, calls virsh to find libvirt network interfaces.
+#
+
+# -----------------------------------------------------------------------------
+
+# the system path is cleared by cgroup-network
+# shellcheck source=/dev/null
+[ -f /etc/profile ] && source /etc/profile
+
+export LC_ALL=C
+
+PROGRAM_NAME="$(basename "${0}")"
+
+logdate() {
+    date "+%Y-%m-%d %H:%M:%S"
+}
+
+log() {
+    local status="${1}"
+    shift
+
+    echo >&2 "$(logdate): ${PROGRAM_NAME}: ${status}: ${*}"
+
+}
+
+warning() {
+    log WARNING "${@}"
+}
+
+error() {
+    log ERROR "${@}"
+}
+
+info() {
+    log INFO "${@}"
+}
+
+fatal() {
+    log FATAL "${@}"
+    exit 1
+}
+
+debug=0
+debug() {
+    [ "${debug}" = "1" ] && log DEBUG "${@}"
+}
+
+# -----------------------------------------------------------------------------
+# check for BASH v4+ (required for associative arrays)
+
+[ $(( BASH_VERSINFO[0] )) -lt 4 ] && \
+    fatal "BASH version 4 or later is required (this is ${BASH_VERSION})."
+
+# -----------------------------------------------------------------------------
+# parse the arguments
+
+pid=
+cgroup=
+while [ ! -z "${1}" ]
+do
+    case "${1}" in
+        --cgroup) cgroup="${2}"; shift 1;;
+        --pid|-p) pid="${2}"; shift 1;;
+        --debug|debug) debug=1;;
+        *) fatal "Cannot understand argument '${1}'";;
+    esac
+
+    shift
+done
+
+if [ -z "${pid}" ] && [ -z "${cgroup}" ]
+then
+    fatal "Either --pid or --cgroup is required"
+fi
+
+# -----------------------------------------------------------------------------
+
+set_source() {
+    [ ${debug} -eq 1 ] && echo "SRC ${*}"
+}
+
+
+# -----------------------------------------------------------------------------
+# veth interfaces via cgroup
+
+# cgroup-network can detect veth interfaces by itself (written in C).
+# If you seek for a shell version of what it does, check this:
+# https://github.com/netdata/netdata/issues/474#issuecomment-317866709
+
+
+# -----------------------------------------------------------------------------
+# tun/tap interfaces via /proc/PID/fdinfo
+
+# find any tun/tap devices linked to a pid
+proc_pid_fdinfo_iff() {
+    local p="${1}" # the pid
+
+    debug "Searching for tun/tap interfaces for pid ${p}..."
+    set_source "fdinfo"
+    grep "^iff:.*" "${NETDATA_HOST_PREFIX}/proc/${p}/fdinfo"/* 2>/dev/null | cut -f 2
+}
+
+find_tun_tap_interfaces_for_cgroup() {
+    local c="${1}" # the cgroup path
+
+    # for each pid of the cgroup
+    # find any tun/tap devices linked to the pid
+    if [ -f "${c}/emulator/cgroup.procs" ]
+    then
+        local p
+        for p in $(< "${c}/emulator/cgroup.procs" )
+        do
+            proc_pid_fdinfo_iff "${p}"
+        done
+    fi
+}
+
+
+# -----------------------------------------------------------------------------
+# virsh domain network interfaces
+
+virsh_cgroup_to_domain_name() {
+    local c="${1}" # the cgroup path
+
+    debug "extracting a possible virsh domain from cgroup ${c}..."
+
+    # extract for the cgroup path
+    sed -n -e "s|.*/machine-qemu\\\\x2d[0-9]\+\\\\x2d\(.*\)\.scope$|\1|p" \
+           -e "s|.*/machine/\(.*\)\.libvirt-qemu$|\1|p" \
+           <<EOF
+${c}
+EOF
+}
+
+virsh_find_all_interfaces_for_cgroup() {
+    local c="${1}" # the cgroup path
+
+    # the virsh command
+    local virsh
+    # shellcheck disable=SC2230
+    virsh="$(which virsh 2>/dev/null || command -v virsh 2>/dev/null)"
+
+    if [ ! -z "${virsh}" ]
+    then
+        local d
+        d="$(virsh_cgroup_to_domain_name "${c}")"
+
+        if [ ! -z "${d}" ]
+        then
+            debug "running: virsh domiflist ${d}; to find the network interfaces"
+
+            # match only 'network' interfaces from virsh output
+
+            set_source "virsh"
+            "${virsh}" -r domiflist "${d}" |\
+                sed -n \
+                    -e "s|^\([^[:space:]]\+\)[[:space:]]\+network[[:space:]]\+\([^[:space:]]\+\)[[:space:]]\+[^[:space:]]\+[[:space:]]\+[^[:space:]]\+$|\1 \1_\2|p" \
+                    -e "s|^\([^[:space:]]\+\)[[:space:]]\+bridge[[:space:]]\+\([^[:space:]]\+\)[[:space:]]\+[^[:space:]]\+[[:space:]]\+[^[:space:]]\+$|\1 \1_\2|p"
+        else
+            debug "no virsh domain extracted from cgroup ${c}"
+        fi
+    else
+        debug "virsh command is not available"
+    fi
+}
+
+# -----------------------------------------------------------------------------
+
+find_all_interfaces_of_pid_or_cgroup() {
+    local p="${1}" c="${2}" # the pid and the cgroup path
+
+    if [ ! -z "${pid}" ]
+    then
+        # we have been called with a pid
+
+        proc_pid_fdinfo_iff "${p}"
+
+    elif [ ! -z "${c}" ]
+    then
+        # we have been called with a cgroup
+
+        info "searching for network interfaces of cgroup '${c}'"
+
+        find_tun_tap_interfaces_for_cgroup "${c}"
+        virsh_find_all_interfaces_for_cgroup "${c}"
+
+    else
+
+        error "Either a pid or a cgroup path is needed"
+        return 1
+
+    fi
+
+    return 0
+}
+
+# -----------------------------------------------------------------------------
+
+# an associative array to store the interfaces
+# the index is the interface name as seen by the host
+# the value is the interface name as seen by the guest / container
+declare -A devs=()
+
+# store all interfaces found in the associative array
+# this will also give the unique devices, as seen by the host
+last_src=
+# shellcheck disable=SC2162
+while read host_device guest_device
+do
+    [ -z "${host_device}" ] && continue
+
+    [ "${host_device}" = "SRC" ] && last_src="${guest_device}" && continue
+
+    # the default guest_device is the host_device
+    [ -z "${guest_device}" ] && guest_device="${host_device}"
+
+    # when we run in debug, show the source
+    debug "Found host device '${host_device}', guest device '${guest_device}', detected via '${last_src}'"
+
+    if [ -z "${devs[${host_device}]}" ] || [ "${devs[${host_device}]}" = "${host_device}" ]; then
+        devs[${host_device}]="${guest_device}"
+    fi
+
+done < <( find_all_interfaces_of_pid_or_cgroup "${pid}" "${cgroup}" )
+
+# print the interfaces found, in the format netdata expects them
+found=0
+for x in "${!devs[@]}"
+do
+    found=$((found + 1))
+    echo "${x} ${devs[${x}]}"
+done
+
+debug "found ${found} network interfaces for pid '${pid}', cgroup '${cgroup}', run as ${USER}, ${UID}"
+
+# let netdata know if we found any
+[ ${found} -eq 0 ] && exit 1
+exit 0