Change Details

For changing the MTU on `tun` devices, it should not matter whether it is done via using `ifconfig`, which uses a `SIOCSIFMTU` `ioctl()` command or doing it using a `TUNSIFINFO` `ioctl()` command. Without this patch, for IPv6 the new MTU is not used when creating routes. Especially, when initiating TCP connections after increasing the MTU, the old MTU is still used to compute the MSS. Please note the the code change is inspired by [[ https://svnweb.freebsd.org/base/head/sys/net/if.c?view=markup#l2778 | if.c ]].

For changing the MTU on `tun` devices, it should not matter whether it is done via using `ifconfig`, which uses a `SIOCSIFMTU` `ioctl()` command or doing it using a `TUNSIFINFO` `ioctl()` command. Without this patch, for IPv6 the new MTU is not used when creating routes. Especially, when initiating TCP connections after increasing the MTU, the old MTU is still used to compute the MSS. Please note the the code change is inspired by [[ https://svnweb.freebsd.org/base/head/sys/net/if.c?view=markup#l2778 | if.c ]]. As suggested by ae@, add a corresponding fix to the `tap` interface.

For changing the MTU on `tun` devices, it should not matter whether it is done via using `ifconfig`, which uses a `SIOCSIFMTU` `ioctl()` command or doing it using a `TUNSIFINFO` `ioctl()` command. Without this patch, for IPv6 the new MTU is not used when creating routes. Especially, when initiating TCP connections after increasing the MTU, the old MTU is still used to compute the MSS. Please note the the code change is inspired by [[ https://svnweb.freebsd.org/base/head/sys/net/if.c?view=markup#l2778 | if.c ]]. As suggested by ae@, add a corresponding fix to the `tap` interface.