Subject: Re: getting UDP destination port/addresses
To: None <>
From: Michael Richardson <>
List: tech-net
Date: 01/07/2001 20:09:15
>>>>> "Andrew" == Andrew Brown <> writes:
    >> My recollection was that there was some way to get the destination
    >> address/port to which an UDP packet was sent by toggle either options to
    >> recvmsg(), or via setsockopt(). The option was in 4.3, I'm sure... But I
    >> haven't used it since.
    >> Has it disappeared?
    >> I hate having to open a socket for each address that exists (a la BIND,
    >> etc...) , and this is NetBSD specific.

    Andrew> using IP_RECVDSTADDR and recvmsg(2) (instead of read(2), recv(2), or
    Andrew> recvfrom(2)) works just fine for me.

  that's the thing I'm talking about.
  Where is it documented? recvmsg(2) doesn't mention it...

  How do I get at it? In the msg_control?

  I have always found getting documentation on specific ioctls/setsockopts/flags
to be a problem.

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