nfl.sh
#!/bin/bash
set -euo pipefail
_nfl() {
local cur prev words cword
_init_completion || return
if [ "$cword" = 1 ]; then
COMPREPLY=($(compgen -W 'download upload' -- "$cur"))
elif [ "$cword" = 2 ]; then
_available_interfaces
fi
}
main() {
local hook ifname interface limit cmds
case "${1:-}" in
download)
hook='input'
ifname='iifname'
;;
upload)
hook='output'
ifname='oifname'
;;
'')
sudo nft 'add table inet nfl; list table inet nfl'
return
;;
*)
exit 1
;;
esac
if [[ "$2" =~ ^[[:digit:]] ]]; then
interface=$(ip route list | sed -nE '/^default via \S+ dev (\S+).*$/{s//\1/p;q}')
limit="$2"
else
interface="$2"
limit="$3"
fi
cmds="add table inet nfl; add chain inet nfl ${interface}_$hook { type filter hook $hook priority filter; }"
if [ "$limit" != 0 ]; then
cmds="$cmds; flush chain inet nfl ${interface}_$hook; add rule inet nfl ${interface}_$hook $ifname ${interface} meta l4proto { tcp, udp } limit rate over $limit mbytes/second burst 1 mbytes drop"
else
cmds="$cmds; delete chain inet nfl ${interface}_$hook"
fi
sudo nft "$cmds"
}
main "$@"
用法：
# limit download speed of the default interface to 1MiB
nfl download 1
# change download speed of the default interface to 3MiB
nfl download 3
# remove download speed limitation of the default interface
nfl download 0
# limit upload speed of wlp0s20f3 to 3MiB
nfl upload wlp0s20f3 3
# remove upload speed limitation of wlp0s20f3
nfl upload wlp0s20f3 0
# show content of the nfl table
nfl