Re: [PATCH] dracut-module-setup: Fix routing failure on multipath route

[Dave Young]

On 11/15/18 at 02:18pm, Kairui Song wrote:
> Currently we still don't support multipath route, when parsing multipath
> route kdumpctl will wrong consider 'nexthop' as the destination address,
> and raise errors in second kernel.
>
> When multipath route is in use, ip route output should be like this:
> $ /sbin/ip route show
> default via 192.168.122.1 dev ens1 proto dhcp metric 100
> 192.168.122.0/24 dev ens1 proto kernel scope link src 192.168.122.161 metric 100
> 192.168.122.8
>    nexthop via 192.168.122.1 dev ens1 weight 50
>    nexthop via 192.168.122.2 dev ens1 weight 5
>
> As we won't care about HA/performance, simply use the rule with highest
> weight and ignore the rest.
>
> dracut-module-setup.sh | 41 ++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 40 insertions(+), 1 deletion(-)
>
> diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
> index 2f9d762..7499678 100755
> --- a/dracut-module-setup.sh
> +++ b/dracut-module-setup.sh
> @@ -126,7 +126,8 @@ kdump_static_ip() {
>          echo -n "${_srcaddr}::${_gateway}:${_netmask}::"
>      fi
> /sbin/ip $_ipv6_flag route show | grep -v default | grep ".*via.* $_netdev " |\
> /sbin/ip $_ipv6_flag route show | grep -v default |\
> grep ".*via.* $_netdev " | grep -v "^[[:space:]]*nexthop" |\
> while read _route; do
>     _target=`echo $_route | cut -d ' ' -f1`
>     _nexthop=`echo $_route | cut -d ' ' -f3`
>
> @@ -136,6 +137,44 @@ kdump_static_ip() {
>          fi
>          echo "rd.route=$_target:$_nexthop:$_netdev"
>      done >> ${initdir}/etc/cmdline.d/45route-static.conf
> kdump_handle_mulitpath_route $_netdev $_srcaddr
>
> +}
>
> +kdump_handle_mulitpath_route() {
> local _netdev="$1" _srcaddr="$2" _ipv6_flag
> local _target _nexthop _route _weight _max_weight _rule
> if is_ipv6_address $_srcaddr; then
>    _ipv6_flag="-6"
> fi
> while IFS="" read _route; do
>    if [[ "$_route" =~ [[:space:]]+nexthop ]]; then
>        _route=$(echo "$_route" | sed -e 's/^[[:space:]]*//')
>        # Parse multipath route, using previous _target
>        [[ "$_target" == 'default' ]] && continue
>        [[ "$_route" =~ .*via.*\ $_netdev ]] || continue
>        _weight=`echo "$_route" | cut -d ' ' -f7`
>        if [[ "$_weight" -gt "$_max_weight" ]]; then
>            _nexthop=`echo "$_route" | cut -d ' ' -f3`
>            _max_weight=$_weight
>            if [ "x" !=  "x"$_ipv6_flag ]; then
>                _rule="rd.route=[$_target]:[$_nexthop]:$_netdev"
>            else
>                _rule="rd.route=$_target:$_nexthop:$_netdev"
>            fi
>        fi
>    else
>        [[ -n "$_rule" ]] && echo "$_rule"
>        _target=`echo "$_route" | cut -d ' ' -f1`
>        _rule="" _max_weight=0 _weight=0
>    fi
> done >> ${initdir}/etc/cmdline.d/45route-static.conf\
>    < <(/sbin/ip $_ipv6_flag route show)
> [[ -n $_rule ]] && echo $_rule >> ${initdir}/etc/cmdline.d/45route-static.conf
>
> }
> kdump_get_mac_addr() {
>
> 2.17.1

Baoquan, Pingfan, can you review this patch?

Thanks
Dave