[RP-PPPoE] pppoe-server: problem with duplicated PADO's

[Dianne Skoll]

Hi,

> thanks for the quick response.
> As requested, I will send you the strace output as an attachment.

OK.  The important lines are these ones; I have added numbers for
convenience:

[1] recvfrom(3, "\xff\xff\xff\xff\xff\xff\x5e\x09\x87\x21\xdc\xee\x88\x63\x11\x09\x00\x00\x00\x0c\x01\x01\x00\x00\x01\x03\x00\x04\x80\x06\x00\x00"..., 1528, 0, NULL, NULL) = 60

[2] sendto(3, "\x5e\x09\x87\x21\xdc\xee\x08\x00\x27\x2d\x3f\x3b\x88\x63\x11\x07\x00\x00\x00\x32\x01\x02\x00\x05\x70\x70\x70\x6f\x65\x01\x01\x00"..., 70, 0, NULL, 0) = 70

[3] recvfrom(3, "\xff\xff\xff\xff\xff\xff\x5e\x09\x87\x21\xdc\xee\x88\x63\x11\x09\x00\x00\x00\x0c\x01\x01\x00\x00\x01\x03\x00\x04\x80\x06\x00\x00"..., 1528, 0, NULL, NULL) = 60

[4] sendto(3, "\x5e\x09\x87\x21\xdc\xee\x08\x00\x27\x2d\x3f\x3b\x88\x63\x11\x07\x00\x00\x00\x32\x01\x02\x00\x05\x70\x70\x70\x6f\x65\x01\x01\x00"..., 70, 0, NULL, 0) = 70

In line 1, we see an incoming Ethernet packet.

Destination address = 0xffffffffffff - Ethernet broadcast
Source address      = 0x5e098721dcee - MAC address of sender
Ether type          = 0x8863         - PPPoE discovery
Version             = 0x1
Type                = 0x1
CODE                = 0x09           - PADI packet

Line 2 is the server responding with a PADO packet (code 0x07)

Line 3 is the server receiving *another* PADI packet.  In fact, it's identical
to line 1.

So somehow, the client (or something?) is sending two PADI packets, or
somehow the kernel is lying to the PPPoE server and returning two PADI
packets where only one was received on the network.

Regards,

Dianne.