PPPD error: Couldn't attach to interface unit 0: Invalid Argument - PPP

This is a discussion on PPPD error: Couldn't attach to interface unit 0: Invalid Argument - PPP ; Hi All, I have written a PPP application that runs ppp on the slave side of a pseudo terminal. I have multilink enabled in my PPP options file. When i run the application i am getting the following error on ...

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Thread: PPPD error: Couldn't attach to interface unit 0: Invalid Argument

  1. PPPD error: Couldn't attach to interface unit 0: Invalid Argument

    Hi All,

    I have written a PPP application that runs ppp on the slave side of a
    pseudo terminal. I have multilink enabled in my PPP options file. When
    i run the application i am getting the following error on a Linux PC

    Couldn't attach to interface unit 0: Invalid Argument

    Log says, the MP bundle creation is is successful after that i am
    getting this error. What does this error mean in Linux PPP Generic
    module ?.


    Also, i have to do some processing on the packets received on the
    slave side of the pseudo terminal. If i disable the "sync" option from
    my options file, the packets received are stuffed withe 0x7E 0x7D
    flags. What i observe is, only the LCP packets are stuffed with 0x7D
    flag, and the IPCP packets are not stuffed..?Is there any problem with
    my application or where can i see the code in Linux Kernel which does
    this byte stuffing..?

    Thanks,
    Vanitha

  2. Re: PPPD error: Couldn't attach to interface unit 0: Invalid Argument

    vanitha@agilis.st.com.sg (Vanitha) writes:
    > Also, i have to do some processing on the packets received on the
    > slave side of the pseudo terminal. If i disable the "sync" option from
    > my options file, the packets received are stuffed withe 0x7E 0x7D
    > flags. What i observe is, only the LCP packets are stuffed with 0x7D
    > flag, and the IPCP packets are not stuffed..?Is there any problem with
    > my application or where can i see the code in Linux Kernel which does
    > this byte stuffing..?


    I think you're looking at the effect of the ACCM. The default in RFC
    1662 is FFFFFFFF hex -- meaning that all ASCII control characters (00
    through 1F hex) are escaped, along with the default 7D and 7E
    characters.

    pppd tries to negotiate the ACCM to 0, which disables escaping on
    control characters. Use "default-asyncmap" to disable this feature if
    necessary.

    --
    James Carlson, IP Systems Group
    Sun Microsystems / 1 Network Drive 71.234W Vox +1 781 442 2084
    MS UBUR02-212 / Burlington MA 01803-2757 42.497N Fax +1 781 442 1677

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