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 #
16 BPF_FILE=xdp2skb_meta_kern.o
17 DIR=$(dirname $0)
18
19 [ -z "$TC" ] && TC=tc
20 [ -z "$IP" ] && IP=ip
21
22 function 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 --
34 function err() {
35 local exitcode=$1
36 shift
37 echo "ERROR: $@" >&2
38 exit $exitcode
39 }
40
41 function info() {
42 if [[ -n "$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
51 function _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 $@\""
66 fi
67 fi
68 }
69 function call_tc() {
70 _call_cmd "$TC" "" "$@"
71 }
72 function call_tc_allow_fail() {
73 _call_cmd "$TC" "allow_fail" "$@"
74 }
75 function call_ip() {
76 _call_cmd "$IP" "" "$@"
77 }
78
79 ## --- Parse command line arguments / parameters ---
80 # Using external program "getopt" to get --long-options
81 OPTIONS=$(getopt -o vfhd: \
82 --long verbose,flush,help,list,dev:,dry-run -- "$@")
83 if (( $? != 0 )); then
84 err 4 "Error calling getopt"
85 fi
86 eval set -- "$OPTIONS"
87
88 unset DEV
89 unset FLUSH
90 while 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=$VERBOSE" >&2
100 shift
101 ;;
102 --dry-run )
103 DRYRUN=yes
104 VERBOSE=yes
105 info "Dry-run mode: enable VERBOSE and don't call TC+IP" >&2
106 shift
107 ;;
108 -f | --flush )
109 FLUSH=yes
110 shift
111 ;;
112 --list )
113 LIST=yes
114 shift
115 ;;
116 -- )
117 shift
118 break
119 ;;
120 -h | --help )
121 usage;
122 exit 0
123 ;;
124 * )
125 shift
126 break
127 ;;
128 esac
129 done
130
131 FILE="$DIR/$BPF_FILE"
132 if [[ ! -e $FILE ]]; then
133 err 3 "Missing BPF object file ($FILE)"
134 fi
135
136 if [[ -z $DEV ]]; then
137 usage
138 err 2 "Please specify network device -- required option --dev"
139 fi
140
141 ## -- Function calls --
142
143 function 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
151 function 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
159 function 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
168 function 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
176 function 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
192 function 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
207 if [[ -n $FLUSH ]]; then
208 flush_tc $DEV
209 flush_xdp $DEV
210 exit 0
211 fi
212
213 if [[ -n $LIST ]]; then
214 list_tc $DEV
215 list_xdp $DEV
216 exit 0
217 fi
218
219 attach_tc_mark $DEV $FILE
220 attach_xdp_mark $DEV $FILE
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