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 $mac" >&2
31
32    # Delete and static gateways and neighbors
33    while read entry; do
34        eval "$(echo "$entry" | JSONToVars)" || return
35        echo "Deleting neighbor $object"
36        DeleteObject "$service" "$object" || true
37    done < <(GetNeighborObjects "$netdev" 2>/dev/null)
38
39    busctl set-property xyz.openbmc_project.Network "$(EthObjRoot "$NCSI_IF")" \
40        xyz.openbmc_project.Network.EthernetInterface DefaultGateway6 s "" || true
41
42    # In case we don't have a base network file, make one
43    net_file=/run/systemd/network/00-bmc-$NCSI_IF.network
44    printf '[Match]\nName=%s\n[Network]\nDHCP=false\nIPv6AcceptRA=false\nLinkLocalAddressing=yes' \
45        "$NCSI_IF" >$net_file
46
47    # Override any existing gateway info
48    mkdir -p $net_file.d
49    printf '[Network]\nGateway=%s\n[Neighbor]\nMACAddress=%s\nAddress=%s' \
50        "$rtr" "$mac" "$rtr" >$net_file.d/10-gateway.conf
51
52    networkctl reload && networkctl reconfigure "$NCSI_IF" || true
53
54    retries=-1
55    old_mac="$mac"
56    old_rtr="$rtr"
57}
58
59retries=1
60w=60
61while true; do
62    start=$SECONDS
63    args=(-m "$NCSI_IF" -w $(( w * 1000 )))
64    if (( retries > 0 )); then
65        args+=(-r "$retries")
66    else
67        args+=(-d)
68    fi
69    while read line; do
70        if [ -z "$line" ]; then
71            lifetime=
72            mac=
73        elif [[ "$line" =~ ^Router' 'lifetime' '*:' '*([0-9]*) ]]; then
74            lifetime="${BASH_REMATCH[1]}"
75        elif [[ "$line" =~ ^Source' 'link-layer' 'address' '*:' '*([a-fA-F0-9:]*)$ ]]; then
76            mac="${BASH_REMATCH[1]}"
77        elif [[ "$line" =~ ^from' '(.*)$ ]]; then
78            rtr="${BASH_REMATCH[1]}"
79            set_rtr || true
80            lifetime=
81            mac=
82            rtr=
83        fi
84    done < <(exec rdisc6 "${args[@]}" 2>/dev/null)
85    # If rdisc6 exits early we still want to wait the full `w` time before
86    # starting again.
87    (( timeout = start + w - SECONDS ))
88    sleep $(( timeout < 0 ? 0 : timeout ))
89done
90