tree 99e7aa6cc85d3cd4ed0caaa6f1e5aea79e7cfcba
parent ddd872bc3098f9d9abe1680a6b2013e59e3337f7
author Alexei Starovoitov <ast@plumgrid.com> 1417475195 -0800
committer David S. Miller <davem@davemloft.net> 1417844852 -0800

net: sock: allow eBPF programs to be attached to sockets

introduce new setsockopt() command:

setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &prog_fd, sizeof(prog_fd))

where prog_fd was received from syscall bpf(BPF_PROG_LOAD, attr, ...)
and attr->prog_type == BPF_PROG_TYPE_SOCKET_FILTER

setsockopt() calls bpf_prog_get() which increments refcnt of the program,
so it doesn't get unloaded while socket is using the program.

The same eBPF program can be attached to multiple sockets.

User task exit automatically closes socket which calls sk_filter_uncharge()
which decrements refcnt of eBPF program

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>