SO_BINDTODEVICE or equivalent?

Attila Nagy bra at fsn.hu
Thu Apr 19 05:47:50 UTC 2012


   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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