Messages in this thread | | | Date | Sat, 30 Apr 2011 04:07:10 +0400 | From | Alexey Kuznetsov <> | Subject | Re: [PATCH] ipv6: fix incorrect unregistration of sysctl when last ip deleted |
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On Fri, Apr 29, 2011 at 02:58:24PM -0700, John Gardiner Myers wrote: > If the device isn't going away, then the ip6_ptr shouldn't be zeroed, > the /proc/net/dev_snmp6 entry shouldn't be deregistered,
Actually, you are right. Tuned interface parameters and disabling/enabling IPv6 (or IP, or whatever) should be different things. We just did not have an interface to disable protocol, but leave in*_dev, so that they were merged.
When doing this just keep in mind that addrconf_ifdown(how = 0) did _not_ mean disabling IPv6. (Probably, it does now in fact, I do not know. But it definitely did not mean this in the past).
Look, addrconf_ifdown(how = 0) was executed only when the physical device is down, so that we could neither receive nor send over this interface. If the device is UP, addrconf_ifdown(how = 0) did not prohibit sending/receiving IPv6. Actually, logically, addrconf_ifdown(how = 0) on UP interface must be followed by immediate restart of autoconfiguration, because interface is still actually UP. See?
So, to implement this you should verify that IPv6 packets are not sent/received over disabled interface (at least over interface with illegal mtu :-)). And add some flag in in6_dev meaning that IPv6 is actually disabled. So that f.e. after occasional ifconfig eth0 down; ifconfig eth0 up autoconfiguration would not resume IPv6 (the thing which we could not even implement with destroying in6_dev, but definitely wanted).
Alexey
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