On Tue, Jul 02, 2019 at 05:12:01PM +0200, Phil Sutter wrote: > When trying to delete user-defined chains in a large ruleset, > iptables-nft aborts with "No buffer space available". This can be > reproduced using the following script: > > | #! /bin/bash > | iptables-nft-restore <( > | > | echo "*filter" > | for i in $(seq 0 200000);do > | printf ":chain_%06x - [0:0]\n" $i > | done > | for i in $(seq 0 200000);do > | printf -- "-A INPUT -j chain_%06x\n" $i > | printf -- "-A INPUT -j chain_%06x\n" $i > | done > | echo COMMIT > | > | ) > | iptables-nft -X > > Note that calling 'iptables-nft -F' before the last call avoids the > issue. Also, correct behaviour is indicated by a different error > message, namely: > > | iptables v1.8.3 (nf_tables): CHAIN_USER_DEL failed (Device or resource busy): chain chain_000000 > > The used multiplier value is a result of trial-and-error, it is the > first one which eliminated the ENOBUFS condition. This is triggering a lots of errors (ack messages) to userspace. Could you estimate the buffer size based on the number of commands? mnl_batch_talk() is called before iterating over the list of commands, so this number is already in place. Then, pass it to mnl_nft_socket_sendmsg(). I'd suggest you add a mnl_set_rcvbuffer() too. You could assume that getpagesize() is the maximum size for an acknoledgment. Thanks.
