netfilter: nft_log: restrict the log prefix length to 127

First, log prefix will be truncated to NF_LOG_PREFIXLEN-1, i.e. 127, at nf_log_packet(), so the extra part is useless. Second, after adding a log rule with a very very long prefix, we will fail to dump the nft rules after this _special_ one, but acctually, they do exist. For example: # name_65000=$(printf "%0.sQ" {1..65000}) # nft add rule filter output log prefix "$name_65000" # nft add rule filter output counter # nft add rule filter output counter # nft list chain filter output table ip filter { chain output { type filter hook output priority 0; policy accept; } } So now, restrict the log prefix length to NF_LOG_PREFIXLEN-1.

LZLiping Zhang committed 9 years ago