[LEDE-DEV] [netifd] Fix incorrect eui64 IPv6 address with ula prefix for br-lan

[Hans Dedecker]

On Tue, Dec 12, 2017 at 1:05 PM, John Crispin <john at phrozen.org> wrote:
>
>
> On 04/12/17 07:04, wendy2001011 at 163.com wrote:
>>
>> From: Wendy Wu <wendy2001011 at 163.com>
>>
>> Issue description:
>> Configurate /etc/config/network,
>> Set the ula_prefix in globals section,
>> config globals 'globals'
>>          option ula_prefix 'fdc7:8830:f3be::/48'
>> Add the following option in 'lan' interface,
>> option ip6ifaceid 'eui64'
>> Then execute /etc/init.d/network, the br-lan ipv6 address with ula_prefix
>> is incorrect.
>> Result see the following, fdc7:8830:f3be:0:200:ff:fe00:0/64 is incorrect
>> address
>> root at mygateway:~# ifconfig br-lan
>>      br-lan    Link encap:Ethernet  HWaddr E0:B9:E5:66:94:DE
>>                inet addr:192.168.1.1  Bcast:192.168.1.255
>> Mask:255.255.255.0
>>                inet6 addr: fe80::e2b9:e5ff:fe66:94de/64 Scope:Link
>>                inet6 addr: fdc7:8830:f3be:0:200:ff:fe00:0/64 Scope:Global
>>                inet6 addr: 4085:6666:f:e7e0:e2b9:e5ff:fe66:94de/64
>> Scope:Global
>>                UP BROADCAST RUNNING ALLMULTI MULTICAST  MTU:1500  Metric:1
>>                RX packets:17 errors:0 dropped:0 overruns:0 frame:0
>>                TX packets:281 errors:0 dropped:0 overruns:0 carrier:0
>>                collisions:0 txqueuelen:0
>>                RX bytes:2262 (2.2 KiB)  TX bytes:111905 (109.2 KiB)
>>
>> After the fix, fdc7:8830:f3be:0:e2b9:e5ff:fe66:94de/64 is correct address
>> See the following,
>> root at mygateway:~# ifconfig br-lan
>>      br-lan    Link encap:Ethernet  HWaddr E0:B9:E5:66:94:DE
>>                inet addr:192.168.1.1  Bcast:192.168.1.255
>> Mask:255.255.255.0
>>                inet6 addr: fe80::e2b9:e5ff:fe66:94de/64 Scope:Link
>>                inet6 addr: 4085:6666:f:b130:e2b9:e5ff:fe66:94de/64
>> Scope:Global
>>                inet6 addr: fdc7:8830:f3be:0:e2b9:e5ff:fe66:94de/64
>> Scope:Global
>>                UP BROADCAST RUNNING ALLMULTI MULTICAST  MTU:1500  Metric:1
>>                RX packets:2462 errors:0 dropped:0 overruns:0 frame:0
>>                TX packets:31072 errors:0 dropped:0 overruns:0 carrier:0
>>                collisions:0 txqueuelen:0
>>                RX bytes:115038 (112.3 KiB)  TX bytes:12676812 (12.0 MiB)
>>
>> Root cause:
>> When eui64 ipv6 address with ula_prefix for br-lan is created, the lan
>> interface setting has not been ready.
>> So The mac address for br-lan is null, and the eui64 address with
>> ula_prefix is incorrect.
>>
>> Solution:
>> Put the ula_prefix global initial part after device pending
>>
>> Signed-off-by: wendy wu <wendy2001011 at 163.com>
>> ---
>>   config.c | 20 ++++++++++++++++----
>>   1 file changed, 16 insertions(+), 4 deletions(-)
>>
>> diff --git a/config.c b/config.c
>> index 21791af..a494e84 100644
>> --- a/config.c
>> +++ b/config.c
>> @@ -310,10 +310,6 @@ config_init_globals(void)
>>         if (!globals)
>>                 return;
>>   -     const char *ula_prefix = uci_lookup_option_string(
>> -                       uci_ctx, globals, "ula_prefix");
>> -       interface_ip_set_ula_prefix(ula_prefix);
>> -
>>         const char *default_ps = uci_lookup_option_string(
>>                         uci_ctx, globals, "default_ps");
>>   @@ -324,6 +320,21 @@ config_init_globals(void)
>>                         config_parse_global_ps_val(globals,
>> "default_rps_flow_cnt"));
>>   }
>>   +static void
>> +config_init_globals_ula(void)
>> +{
>> +        struct uci_section *globals = uci_lookup_section(
>> +                        uci_ctx, uci_network, "globals");
>> +        if (!globals)
>> +                return;
>> +
>> +        const char *ula_prefix = uci_lookup_option_string(
>> +                        uci_ctx, globals, "ula_prefix");
>> +
>> +        interface_ip_set_ula_prefix(ula_prefix);
>> +
>> +}
>> +
>>   static void
>>   config_parse_wireless_device(struct uci_section *s)
>>   {
>> @@ -447,6 +458,7 @@ config_init_all(void)
>>         device_reset_old();
>>         device_init_pending();
>> +        config_init_globals_ula();
>
> @Hans: can we just move config_init_globals() here ?
The proposed patch does not fix the root cause of the problem being
a race condition in interface_set_prefix_address when eui64 is configured
as ip6ifaceid.
The root cause is fixed by
http://lists.infradead.org/pipermail/lede-dev/2017-December/010320.html
while further issues were fixed in
http://lists.infradead.org/pipermail/lede-dev/2017-December/010319.html.

Hans
>
>     John
>
>>         vlist_flush(&interfaces);
>>         device_free_unused(NULL);
>>         interface_refresh_assignments(false);
>
>