Re: SOCK_RAW does not receive broadcast (with VLAN unless PROMISC)

[Gil Beniamini <gil.beniamini@gmail.com>]

Dear Patrick,
Below is my try to add vlan-id 24 on eth1, followed by "ip -d link list":
root@StudentsHPA:/home/hpa# vconfig add eth1 24
ERROR: trying to add VLAN #24 to IF -:eth1:-  error: File exists

root@StudentsHPA:/home/hpa# ip -d link list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP qlen 100
    link/ether 00:15:17:1e:27:fa brd ff:ff:ff:ff:ff:ff
3: eth1: <BROADCAST,MULTICAST,NOARP,PROMISC,UP,LOWER_UP> mtu 1500
qdisc pfifo_fast state UP qlen 100
    link/ether 00:15:17:1e:e8:46 brd ff:ff:ff:ff:ff:ff
4: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP qlen 100
    link/ether 00:15:17:1e:e8:47 brd ff:ff:ff:ff:ff:ff
5: vlan24@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
noqueue state UP
    link/ether 00:15:17:1e:27:fa brd ff:ff:ff:ff:ff:ff
    vlan id 24 <REORDER_HDR>
6: vlan31@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
noqueue state UP
    link/ether 00:15:17:1e:27:fa brd ff:ff:ff:ff:ff:ff
    vlan id 31 <REORDER_HDR>
7: vlan32@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
noqueue state UP
    link/ether 00:15:17:1e:27:fa brd ff:ff:ff:ff:ff:ff
    vlan id 32 <REORDER_HDR>
8: pan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN
    link/ether 42:fe:3a:c7:dd:96 brd ff:ff:ff:ff:ff:ff
Thanks Gil


On Wed, Jun 10, 2009 at 5:32 PM, Patrick McHardy<kaber@trash.net> wrote:
> Again, please don't top post.
>
> Gil Beniamini wrote:
>>
>> My application is a "proxy" and need to support few VLANs (for example
>> vlan 24).
>> I define all vlans on interface 'eth0' which is my "out i/f", while
>> the other interface 'eth1' (used as "in i/f") I use with PF_PACKET /
>> SOCK_RAW in order to handle VLANs by my application (starting with
>> "arp broadcast").
>> When I try to define the same (relevant VLAN) on eth1 (inorder to
>> check your suggestion), I get "Error: trying to add VLAN #24 to IF
>> -:eth1:- error: file exist".
>> It seems that linux does not allow to define the same VLAN # on more
>> than a single i/f?!
>
> No, that has got to be a mistake. You can use the same ID once
> per underlying device:
>
> # ip -d link list
>
> 4: vlan0@dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN
>    link/ether d6:1f:c0:bd:b2:ec brd ff:ff:ff:ff:ff:ff
>    vlan id 1000 <REORDER_HDR>
> 6: vlan1@dummy1: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN
>    link/ether 8a:17:13:5d:87:1a brd ff:ff:ff:ff:ff:ff
>    vlan id 1000 <REORDER_HDR>
>
> If it doesn't work for you, please post the full commands
> and ip -d link list output you used.
>