fff-ra: Use dhcp leasetime for preferred and valid lifetime #233

fbl · 2022-03-31T20:18:40+02:00

fbl commented

2022-03-31 20:18:40 +02:00

When advertising network prefixes gathered from the interface, odhcpd
sets the preferred and valid lifetime of those prefixes in the router
advertisement to the values set for those addresses on the interface.

When prefixes are configured statically (as done in our firmware), this
means that odhcp announces these prefixes for SLAAC with infinite
preferred and valid lifetimes.

While this does not seem like a problem at first, it hurts significantly
when configuration errors are made or cables are plugged into the wrong
ports, because those addresses never vanish from devices anymore, as long
as they are powered up. Also, it makes it impossible to change prefixes
without gracefully shutting down the RA server, so it can announce zero
lifetimes for previously announced prefixes.

Sadly, odhcp does not have an option to configure these lifetimes
explicitly, but it is possible to limit these lifetimes to the lease
time configured and used for the DHCP functionality of odhcpd.
Enable the appropriate 'ra_useleasetime' option to reduce impact of the
before mentioned problems.

Fixes: #142

When advertising network prefixes gathered from the interface, odhcpd sets the preferred and valid lifetime of those prefixes in the router advertisement to the values set for those addresses on the interface. When prefixes are configured statically (as done in our firmware), this means that odhcp announces these prefixes for SLAAC with infinite preferred and valid lifetimes. While this does not seem like a problem at first, it hurts significantly when configuration errors are made or cables are plugged into the wrong ports, because those addresses never vanish from devices anymore, as long as they are powered up. Also, it makes it impossible to change prefixes without gracefully shutting down the RA server, so it can announce zero lifetimes for previously announced prefixes. Sadly, odhcp does not have an option to configure these lifetimes explicitly, but it is possible to limit these lifetimes to the lease time configured and used for the DHCP functionality of odhcpd. Enable the appropriate 'ra_useleasetime' option to reduce impact of the before mentioned problems. Fixes: #142

fbl added the

layer3

label 2022-03-31 20:18:40 +02:00

fbl added 1 commit 2022-03-31 20:18:41 +02:00

a297651e27 fff-ra: Use dhcp leasetime for preferred and valid lifetime

When advertising network prefixes gathered from the interface, odhcpd
sets the preferred and valid lifetime of those prefixes in the router
advertisement to the values set for those addresses on the interface.

When prefixes are configured statically (as done in our firmware), this
means that odhcp announces these prefixes for SLAAC with infinite
preferred and valid lifetimes.

While this does not seem like a problem at first, it hurts significantly
when configuration errors are made or cables are plugged into the wrong
ports, because those addresses never vanish from devices anymore, as long
as they are powered up. Also, it makes it impossible to change prefixes
without gracefully shutting down the RA server, so it can announce zero
lifetimes for previously announced prefixes.

Sadly, odhcp does not have an option to configure these lifetimes
explicitly, but it is possible to limit these lifetimes to the lease
time configured and used for the DHCP functionality of odhcpd.
Enable the appropriate 'ra_useleasetime' option to reduce impact of the
before mentioned problems.

Fixes: #142
Signed-off-by: Fabian Bläse <fabian@blaese.de>

ChristianD commented

2022-04-03 14:12:14 +02:00

Reviewed-by: Christian Dresel <freifunk@dresel.systems>

```` Reviewed-by: Christian Dresel <freifunk@dresel.systems> ````

ChristianD approved these changes 2022-04-03 14:12:19 +02:00

rohammer commented

2022-04-03 22:39:21 +02:00

Reviewed-by: Robert Langhammer <rlanghammer@web.de>

``` Reviewed-by: Robert Langhammer <rlanghammer@web.de> ```

fbl added this to the 20220405-beta milestone 2022-04-06 13:26:04 +02:00

fbl commented

2022-04-06 23:39:28 +02:00

Applied.

fbl closed this pull request

2022-04-06 23:39:28 +02:00

fbl deleted branch ra

2022-04-06 23:39:31 +02:00

Pull request closed

This pull request cannot be reopened because the branch was deleted.

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Reference: freifunk-franken/firmware#233