Bug 719447

Description of problem: When an interface has 6to4 enabled in it "IPV6TO4INIT=yes" and AUTOCONF enabled "IPV6_AUTOCONF=yes" but no IPv6 Forwarding, Fedora14 correctly enables accept_ra on the base device.  Fedora15 incorrectly disables it by improperly applying the sysctl settings to the wrong interface (the base interface instead of the 6to4 tunnel interface itself.  It's also highly possible this same error may be occurring for other static sit tunnels by disabling autoconf on the base interface instead of the tunnel interface.


Version-Release number of selected component (if applicable):

F14 Works properly.
F15 Broken.

Confirmed in "initscripts-9.30-2.fc15.x86_64"

How reproducible: 100% reliable.


Steps to Reproduce:
1. Enable 6to4 and autoconf on an interface like eth0 and reboot machine.
2. Check for autoconfigured address on eth0.
3. No autoconf address appears.
4. Disable 6to4 in configuration and repeat.
5. Autoconfig address autoconfigures properly.

Actual results: Autoconfiged eth or bridge interfaces fail to accept IPv6 router advertisements in spite of the global accept_ra and forwarding settings.


Expected results: Autoconfiged interfaces should receive and process IPv6 router advertisements when received on a non-tunnel interface when forwarding is disabled and accept_ra is globally enabled and in the config.


Additional info: The change doing the damage is here:

Lines beginning at 614 of network-functions-ipv6 in F15:

# Set sysctls proper (regardless "default")
/sbin/sysctl -e -w net.ipv6.conf.$SYSCTLDEVICE.forwarding=1 >/dev/null 2>&1
/sbin/sysctl -e -w net.ipv6.conf.$SYSCTLDEVICE.accept_ra=0 >/dev/null 2>&1
/sbin/sysctl -e -w net.ipv6.conf.$SYSCTLDEVICE.accept_redirects=0 >/dev/null 2>&1

Same lines in F14 which behave correctly.

Lines beginning at 764 of network-functions-ipv6 in F14:

# Set sysctls proper (regardless "default")
/sbin/sysctl -e -w net.ipv6.conf.$device.forwarding=1 >/dev/null 2>&1
/sbin/sysctl -e -w net.ipv6.conf.$device.accept_ra=0 >/dev/null 2>&1
/sbin/sysctl -e -w net.ipv6.conf.$device.accept_redirects=0 >/dev/null 2>&1

It's highly questionable if we should be forcing forwarding to be 1 even with static sit tunnels in either case when IPv6 Forwarding is disabled by sysctl or config.  It is conceivable to have static sit tunnels where you do not what forwarding.  It's even more questionable in the case of 6to4 auto tunnels to force forwarding to be on.

The other two settings, accept_ra and accept_redirects are reasonable but probably unnecessary on the tunnel interfaces since those should never appear on a tunnel to begin with.  To apply them to the base device, such as the supporting eth device or bridge device, is simply broken behavior.  F14 got it right.  F15 got it very wrong.