udhcpc hook creates duplicate routes

[reinierjh]

I'm not sure if this problem is caused by my own change (restart service when failed) but.
After a few days, ip ro shows the routes to the IPTV interface multiple times.
In the script you check is the NAT rules are already there, but not for the routes.
10.10.0.33 via 10.10.56.1 dev iptv metric 305
10.10.0.33 via 10.10.56.1 dev iptv metric 306
10.10.0.33 via 10.10.56.1 dev iptv metric 307
185.24.175.0/24 via 10.10.56.1 dev iptv metric 305
185.41.48.0/24 via 10.10.56.1 dev iptv metric 305
185.41.48.0/24 via 10.10.56.1 dev iptv metric 306
Restarting the service removes the extra routes, but after a while they reappear.
Probably this is caused by the DHCP renewal.

[fabianishere]

It seems some routes are duplicated with different metrics. This could happen when the ifindex of an interface changes.
To test this hypothesis, in /usr/lib/udm-iptv/udhcpc.hook, could you add the following:

export PATH=/usr/bin:/bin:/usr/sbin:/sbin

# Use busybox if iproute2 is not installed
if ! command -v ip > /dev/null 2>&1; then
    alias ip="busybox ip"
fi

+export IF_METRIC=200

That should resolve the issue if my hypothesis is true.

[reinierjh]

I tried the suggested change, and although the metric started again at 200, it just keeps adding duplicate routes.
10.10.0.33 via 10.10.56.1 dev iptv metric 200
10.10.0.33 via 10.10.56.1 dev iptv metric 201
10.10.0.33 via 10.10.56.1 dev iptv metric 202
185.24.175.0/24 via 10.10.56.1 dev iptv metric 200
185.41.48.0/24 via 10.10.56.1 dev iptv metric 200
185.41.48.0/24 via 10.10.56.1 dev iptv metric 201

[reinierjh]

Almost 24 hours later, and this is stil the case. but because we start at 200 everytime the above stays the same 6 rows.
I try not to touch the router to see if something happens.

[fabianishere]

I guess your ISP sends the routes in different order when renewing the lease, causing a different metric in turn.

See

udm-iptv/udhcpc.hook

Line 80 in 5632542

route_add $dest $gw $num && num=$(($num + 1))

[reinierjh]

As far as i can see the routes only doulble. so no more than 2 routes to the same address exists.
When look in the .hook file:
for i in $router; do
if ! ip -4 route show | grep ^default | grep $i; then
routes
This should only execute route when the route is not found.
On my machine ip -4 route show | grep ^default returns nothing.
Although the routes are already there.