flow_dissector: fix build failure without CONFIG_NET

If boolean CONFIG_BPF_SYSCALL is enabled, kernel/bpf/syscall.c will
call flow_dissector functions from net/core/flow_dissector.c.

This causes this build failure if CONFIG_NET is disabled:

    kernel/bpf/syscall.o: In function `__x64_sys_bpf':
    syscall.c:(.text+0x3278): undefined reference to
    `skb_flow_dissector_bpf_prog_attach'
    syscall.c:(.text+0x3310): undefined reference to
    `skb_flow_dissector_bpf_prog_detach'
    kernel/bpf/syscall.o:(.rodata+0x3f0): undefined reference to
    `flow_dissector_prog_ops'
    kernel/bpf/verifier.o:(.rodata+0x250): undefined reference to
    `flow_dissector_verifier_ops'

Analogous to other optional BPF program types in syscall.c, add stubs
if the relevant functions are not compiled and move the BPF_PROG_TYPE
definition in the #ifdef CONFIG_NET block.

Fixes: d58e468b1112 ("flow_dissector: implements flow dissector BPF hook")
Reported-by: Randy Dunlap <[email protected]>
Signed-off-by: Willem de Bruijn <[email protected]>
Acked-by: Randy Dunlap <[email protected]> # build-tested
Acked-by: Yonghong Song <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>

0 files changed, 0 insertions, 0 deletions