1#!/bin/bash 2# Copyright 2021 Google LLC 3# 4# Licensed under the Apache License, Version 2.0 (the "License"); 5# you may not use this file except in compliance with the License. 6# You may obtain a copy of the License at 7# 8# http://www.apache.org/licenses/LICENSE-2.0 9# 10# Unless required by applicable law or agreed to in writing, software 11# distributed under the License is distributed on an "AS IS" BASIS, 12# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13# See the License for the specific language governing permissions and 14# limitations under the License. 15 16[[ -n ${gbmc_br_nft_lib-} ]] && return 17 18# shellcheck source=meta-google/recipes-google/networking/network-sh/lib.sh 19source /usr/share/network/lib.sh || exit 20 21gbmc_br_nft_pfx= 22 23gbmc_br_nft_update() { 24 printf 'gBMC Bridge input firewall for %s\n' \ 25 "${gbmc_br_nft_pfx:-(deleted)}" >&2 26 27 local contents= 28 contents+='table inet filter {'$'\n' 29 contents+=' chain gbmc_br_int_input {'$'\n' 30 if [[ -n ${gbmc_br_nft_pfx-} ]]; then 31 contents+=" ip6 saddr $gbmc_br_nft_pfx" 32 contents+=" ip6 daddr $gbmc_br_nft_pfx accept"$'\n' 33 fi 34 contents+=' }'$'\n' 35 contents+='}'$'\n' 36 37 local rfile=/run/nftables/40-gbmc-br-int.rules 38 mkdir -p "$(dirname "$rfile")" 39 printf '%s' "$contents" >"$rfile" 40 41 # shellcheck disable=SC2015 42 systemctl reset-failed nftables && systemctl --no-block reload-or-restart nftables || true 43} 44 45gbmc_br_nft_hook() { 46 # Match only global IP addresses on the bridge that match the BMC prefix 47 # (<mpfx>:fdxx:). So 2002:af4:3480:2248:fd02:6345:3069:9186 would become 48 # a 2002:af4:3480:2248:fd00/76 rule. 49 # shellcheck disable=SC2154 50 if [[ $change == addr && $intf == gbmcbr && $scope == global ]] && 51 [[ $fam == inet6 && $flags != *tentative* ]]; then 52 local ip_bytes=() 53 if ! ip_to_bytes ip_bytes "$ip"; then 54 echo "gBMC Bridge NFT Invalid IP: $ip" >&2 55 return 1 56 fi 57 if (( ip_bytes[8] != 0xfd )); then 58 return 0 59 fi 60 local i 61 for (( i=9; i<16; i++ )); do 62 ip_bytes["$i"]=0 63 done 64 pfx="$(ip_bytes_to_str ip_bytes)/76" 65 if [[ $action == add && $pfx != "$gbmc_br_nft_pfx" ]]; then 66 gbmc_br_nft_pfx="$pfx" 67 gbmc_br_nft_update 68 fi 69 fi 70} 71 72GBMC_IP_MONITOR_HOOKS+=(gbmc_br_nft_hook) 73 74gbmc_br_nft_lib=1 75