Date: Thu, 19 Apr 2012 07:41:37 +0200 From: Attila Nagy <bra@fsn.hu> To: freebsd-net@freebsd.org Subject: SO_BINDTODEVICE or equivalent? Message-ID: <4F8FA591.4010503@fsn.hu>
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Hi,
I want to solve the classic problem of a DHCP server: listening for
broadcast UDP packets and figuring out what interface a packet has
come in.
The Linux solution is SO_BINDTODEVICE, which according to socket(7):
SO_BINDTODEVICE
Bind this socket to a particular device like "eth0", as
specified in the passed interface name. If the name is an empty
string or the option length is zero, the socket device binding
is removed. The passed option is a variable-length
null-terminated interface name string with the maximum size of
IFNAMSIZ. If a socket is bound to an interface, only packets
received from that particular interface are processed by the
socket. Note that this only works for some socket types,
particularly AF_INET sockets. It is not supported for packet
sockets (use normal [1]bind(2) there).
This makes it possible to listen on selected interfaces for
(broadcast) packets. FreeBSD currently doesn't implement this feature.
Any chances that somebody will do this?
What alternatives would you recommend? Raw packet access (like BPF and
RAW sockets) finally make the application to do more -mainly useless-
work.
Are there any other solutions, which doesn't require additional packet
parsing?
Thanks,
References
1. http://linux.die.net/man/2/bind
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