Parts of libnetfilter_queue deprecated?

While I was looking for ways to move some firewalling functionality into user space (parse packet to decide whether to drop or accept the packet along with some reporting in the drop case), I came across iptable's NFQUEUE target, which, along with libnetfilter_queue, seems to be a perfect match for my use case.
However, parts of the doxygen documentation (at https://www.netfilter.org/projects/libnetfilter_queue/doxygen/html/modules.html )
are marked deprecated (i.e. Queue handling, Library setup, Message parsing functions, and Printing).

I may have missed it while I was searching the netfilter mailing list archives in this context, but I could not find any hint on the reason why these parts of libnetfilter_queue are deprecated (apart from nfq_set_verdict_mark() being marked as deprecated) nor did I find any hint on a replacement. Could you enlighten me here?

1 Answer

These apis are not extensible, they hide too much netlink details.

You can use this example:
http://git.netfilter.org/libnetfilter_queue/tree/examples/nf-queue.c

With old api, you can't set conntrack mark for instance or examine e.g. checksum-not-ready flag.

answer May 25, 2018 by Jagan Mishra

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Parts of libnetfilter_queue deprecated?

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