net: filter: cleanup invocation of internal BPF

Kernel API for classic BPF socket filters is:

sk_unattached_filter_create() - validate classic BPF, convert, JIT
SK_RUN_FILTER() - run it
sk_unattached_filter_destroy() - destroy socket filter

Cleanup internal BPF kernel API as following:

sk_filter_select_runtime() - final step of internal BPF creation.
  Try to JIT internal BPF program, if JIT is not available select interpreter
SK_RUN_FILTER() - run it
sk_filter_free() - free internal BPF program

Disallow direct calls to BPF interpreter. Execution of the BPF program should
be done with SK_RUN_FILTER() macro.

Example of internal BPF create, run, destroy:

  struct sk_filter *fp;

  fp = kzalloc(sk_filter_size(prog_len), GFP_KERNEL);
  memcpy(fp->insni, prog, prog_len * sizeof(fp->insni[0]));
  fp->len = prog_len;

  sk_filter_select_runtime(fp);

  SK_RUN_FILTER(fp, ctx);

  sk_filter_free(fp);

Sockets, seccomp, testsuite, tracing are using different ways to populate
sk_filter, so first steps of program creation are not common.

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

1 files changed, 2 insertions, 4 deletions

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 9d5ae0a2c954..7977b3958e25 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -184,10 +184,8 @@ static inline unsigned int sk_filter_size(unsigned int proglen)
 
 int sk_filter(struct sock *sk, struct sk_buff *skb);
 
-u32 sk_run_filter_int_seccomp(const struct seccomp_data *ctx,
-			      const struct sock_filter_int *insni);
-u32 sk_run_filter_int_skb(const struct sk_buff *ctx,
-			  const struct sock_filter_int *insni);
+void sk_filter_select_runtime(struct sk_filter *fp);
+void sk_filter_free(struct sk_filter *fp);
 
 int sk_convert_filter(struct sock_filter *prog, int len,
 		      struct sock_filter_int *new_prog, int *new_len);