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
16source "$(dirname "${BASH_SOURCE[0]}")"/ncsid_lib.sh
17
18NCSI_IF="$1"
19
20old_rtr=
21old_mac=
22
23function set_rtr() {
24    [ -n "$rtr" -a -n "$lifetime" ] || return
25    [ "$rtr" != "$old_rtr" -a "$mac" != "$old_mac" ] || return
26    # Only valid default routers can be considered, 0 lifetime implies
27    # a non-default router
28    (( lifetime > 0 )) || return
29
30    echo "Setting default router: $rtr at $mac" >&2
31    local svc=xyz.openbmc_project.Network
32    SetStatic "$svc" "$NCSI_IF" || return
33    UpdateGateway "$svc" "$NCSI_IF" "$rtr" || return
34    UpdateNeighbor "$svc" "$NCSI_IF" "$rtr" "$mac" || return
35
36    retries=-1
37    old_mac="$mac"
38    old_rtr="$rtr"
39}
40
41retries=1
42w=60
43while true; do
44    start=$SECONDS
45    args=(-m "$NCSI_IF" -w $(( w * 1000 )))
46    if (( retries > 0 )); then
47        args+=(-r "$retries")
48    else
49        args+=(-d)
50    fi
51    while read line; do
52        if [ -z "$line" ]; then
53            lifetime=
54            mac=
55        elif [[ "$line" =~ ^Router' 'lifetime' '*:' '*([0-9]*) ]]; then
56            lifetime="${BASH_REMATCH[1]}"
57        elif [[ "$line" =~ ^Source' 'link-layer' 'address' '*:' '*([a-fA-F0-9:]*)$ ]]; then
58            mac="${BASH_REMATCH[1]}"
59        elif [[ "$line" =~ ^from' '(.*)$ ]]; then
60            rtr="${BASH_REMATCH[1]}"
61            set_rtr || true
62            lifetime=
63            mac=
64            rtr=
65        fi
66    done < <(exec rdisc6 "${args[@]}" 2>/dev/null)
67    # If rdisc6 exits early we still want to wait the full `w` time before
68    # starting again.
69    (( timeout = start + w - SECONDS ))
70    sleep $(( timeout < 0 ? 0 : timeout ))
71done
72