1#!/bin/bash
  2#
  3# SPDX-License-Identifier: GPL-2.0
  4# Copyright (c) 2018 Jesper Dangaard Brouer, Red Hat Inc.
  5#
  6# Bash-shell example on using iproute2 tools 'tc' and 'ip' to load
  7# eBPF programs, both for XDP and clsbpf.  Shell script function
  8# wrappers and even long options parsing is illustrated, for ease of
  9# use.
 10#
 11# Related to sample/bpf/xdp2skb_meta_kern.c, which contains BPF-progs
 12# that need to collaborate between XDP and TC hooks.  Thus, it is
 13# convenient that the same tool load both programs that need to work
 14# together.
 15#
 16BPF_FILE=xdp2skb_meta_kern.o
 17DIR=$(dirname $0)
 18
 19[ -z "$TC" ] && TC=tc
 20[ -z "$IP" ] && IP=ip
 21
 22function usage() {
 23    echo ""
 24    echo "Usage: $0 [-vfh] --dev ethX"
 25    echo "  -d | --dev     :             Network device (required)"
 26    echo "  --flush        :             Cleanup flush TC and XDP progs"
 27    echo "  --list         : (\$LIST)     List TC and XDP progs"
 28    echo "  -v | --verbose : (\$VERBOSE)  Verbose"
 29    echo "  --dry-run      : (\$DRYRUN)   Dry-run only (echo commands)"
 30    echo ""
 31}
 32
 33## -- General shell logging cmds --
 34function err() {
 35    local exitcode=$1
 36    shift
 37    echo "ERROR: $@" >&2
 38    exit $exitcode
 39}
 40
 41function info() {
 42    if [[ -n "$VERBOSE" ]]; then
 43	echo "# $@"
 44    fi
 45}
 46
 47## -- Helper function calls --
 48
 49# Wrapper call for TC and IP
 50# - Will display the offending command on failure
 51function _call_cmd() {
 52    local cmd="$1"
 53    local allow_fail="$2"
 54    shift 2
 55    if [[ -n "$VERBOSE" ]]; then
 56	echo "$cmd $@"
 57    fi
 58    if [[ -n "$DRYRUN" ]]; then
 59	return
 60    fi
 61    $cmd "$@"
 62    local status=$?
 63    if (( $status != 0 )); then
 64	if [[ "$allow_fail" == "" ]]; then
 65	    err 2 "Exec error($status) occurred cmd: \"$cmd $@\""
 66	fi
 67    fi
 68}
 69function call_tc() {
 70    _call_cmd "$TC" "" "$@"
 71}
 72function call_tc_allow_fail() {
 73    _call_cmd "$TC" "allow_fail" "$@"
 74}
 75function call_ip() {
 76    _call_cmd "$IP" "" "$@"
 77}
 78
 79##  --- Parse command line arguments / parameters ---
 80# Using external program "getopt" to get --long-options
 81OPTIONS=$(getopt -o vfhd: \
 82    --long verbose,flush,help,list,dev:,dry-run -- "$@")
 83if (( $? != 0 )); then
 84    err 4 "Error calling getopt"
 85fi
 86eval set -- "$OPTIONS"
 87
 88unset DEV
 89unset FLUSH
 90while true; do
 91    case "$1" in
 92	-d | --dev ) # device
 93	    DEV=$2
 94	    info "Device set to: DEV=$DEV" >&2
 95	    shift 2
 96	    ;;
 97	-v | --verbose)
 98	    VERBOSE=yes
 99	    # info "Verbose mode: VERBOSE=$VERBOSE" >&2
100	    shift
101	    ;;
102	--dry-run )
103	    DRYRUN=yes
104	    VERBOSE=yes
105	    info "Dry-run mode: enable VERBOSE and don't call TC+IP" >&2
106	    shift
107            ;;
108	-f | --flush )
109	    FLUSH=yes
110	    shift
111	    ;;
112	--list )
113	    LIST=yes
114	    shift
115	    ;;
116	-- )
117	    shift
118	    break
119	    ;;
120	-h | --help )
121	    usage;
122	    exit 0
123	    ;;
124	* )
125	    shift
126	    break
127	    ;;
128    esac
129done
130
131FILE="$DIR/$BPF_FILE"
132if [[ ! -e $FILE ]]; then
133    err 3 "Missing BPF object file ($FILE)"
134fi
135
136if [[ -z $DEV ]]; then
137    usage
138    err 2 "Please specify network device -- required option --dev"
139fi
140
141## -- Function calls --
142
143function list_tc()
144{
145    local device="$1"
146    shift
147    info "Listing current TC ingress rules"
148    call_tc filter show dev $device ingress
149}
150
151function list_xdp()
152{
153    local device="$1"
154    shift
155    info "Listing current XDP device($device) setting"
156    call_ip link show dev $device | grep --color=auto xdp
157}
158
159function flush_tc()
160{
161    local device="$1"
162    shift
163    info "Flush TC on device: $device"
164    call_tc_allow_fail filter del dev $device ingress
165    call_tc_allow_fail qdisc del dev $device clsact
166}
167
168function flush_xdp()
169{
170    local device="$1"
171    shift
172    info "Flush XDP on device: $device"
173    call_ip link set dev $device xdp off
174}
175
176function attach_tc_mark()
177{
178    local device="$1"
179    local file="$2"
180    local prog="tc_mark"
181    shift 2
182
183    # Re-attach clsact to clear/flush existing role
184    call_tc_allow_fail qdisc del dev $device clsact 2> /dev/null
185    call_tc            qdisc add dev $device clsact
186
187    # Attach BPF prog
188    call_tc filter add dev $device ingress \
189	    prio 1 handle 1 bpf da obj $file sec $prog
190}
191
192function attach_xdp_mark()
193{
194    local device="$1"
195    local file="$2"
196    local prog="xdp_mark"
197    shift 2
198
199    # Remove XDP prog in-case it's already loaded
200    # TODO: Need ip-link option to override/replace existing XDP prog
201    flush_xdp $device
202
203    # Attach XDP/BPF prog
204    call_ip link set dev $device xdp obj $file sec $prog
205}
206
207if [[ -n $FLUSH ]]; then
208    flush_tc  $DEV
209    flush_xdp $DEV
210    exit 0
211fi
212
213if [[ -n $LIST ]]; then
214    list_tc  $DEV
215    list_xdp $DEV
216    exit 0
217fi
218
219attach_tc_mark  $DEV $FILE
220attach_xdp_mark $DEV $FILE