On Mon, May 4, 2015 at 11:12 AM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote: > On Mon, 2015-05-04 at 10:41 -0400, John Heffner wrote: > >> Nice idea, seems handy. But a couple (somewhat related) questions: >> >> * Other than convenience, are there reasons not use an existing, more >> general-purpose and portable mechanism like pcap? (Permissions, I >> guess?) > > Very hard to synchronize when say you have 32 listeners sharing a single > port (SO_REUSEPORT), and receive one million SYN per second (when my TCP > listener scaling work is finished). > > libpcap here would be a serious bottleneck, even with a clever FANIN > support on the af_packet sockets, considering use of multiqueue NIC. > >> * Are there conditions where, for security purposes, you don't want an >> application to have access to the raw SYNs? > > Not that we are aware of : We restrict the access to IP + TCP headers, > for the passive part. All information that is available there was > provided by the remote peer on a 'open way' anyway. Makes sense, thanks. -John -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
