Re: Bug #619684: ns2: FTBFS on kfreebsd-*: emulate/net-pcap.cc:537:19: error: 'BIOCIMMEDIATE' was not declared in this scope

[Aron Xu <happyaron.xu@gmail.com>]

On Sat, Apr 16, 2011 at 03:49, YunQiang Su <wzssyqa@gmail.com> wrote:
> I got it.
>
> It used it like this
>
> #if !defined(__linux__)&&!defined(__APPLE__)
>        {
>                int immed = 1;
>                if (ioctl(pfd_, BIOCIMMEDIATE, &immed) < 0) {
>                        fprintf(stderr,
>                                "warning: pcap/live (%s) couldn't set immed\n",
>                                name());
>                        perror("ioctl(BIOCIMMEDIATE)");
>                }
>        }
> #endif
>
> On linux , BIOCIMMEDIATE is not used, but on BSD, it did being used,
> but did *not* include net/bpf.h
>
> Then there are 2 ways to fix this bug:
>    1. also disable the above code block on BSD.
>    2. include net/bpf.h on BSD platform.
>
> Which one is better ?
> --
> YunQiang Su
>

I prefer to attempting to use this piece of code first. Because using
BIOCIMMEDIATE could very probably get some advantages over not using
them on kbsd platforms.

Here is a thread about it in freebsd-arch mailing list:
http://lists.freebsd.org/pipermail/freebsd-arch/2003-November/001446.html

> No.  BIOCIMMEDIATE and non-blocking mode are different.
>
> BIOCIMMEDIATE mode means "make incoming packets
> readable immediately; don't buffer them up until either the
> store buffer is full or the timeout expires".  This is for use in,
> for example, applications that are using BPF to implement
> network protocols, and want to be able to respond
> immediately to incoming packets, as opposed to, for
> example, packet capture applications (tcpdump, Ethereal,
> etc.) which don't necessarily need to immediately show or
> save incoming packets and which might want to try to get
> as many packets as possible per read on the BPF device.


-- 
Regards,
Aron Xu