bpf: Add PROG_TEST_RUN support for sk_lookup programs

Allow to pass sk_lookup programs to PROG_TEST_RUN. User space
provides the full bpf_sk_lookup struct as context. Since the
context includes a socket pointer that can't be exposed
to user space we define that PROG_TEST_RUN returns the cookie
of the selected socket or zero in place of the socket pointer.

We don't support testing programs that select a reuseport socket,
since this would mean running another (unrelated) BPF program
from the sk_lookup test handler.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210303101816.36774-3-lmb@cloudflare.com

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 4c730863fa77..c931bc97019d 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1491,6 +1491,9 @@ int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
 int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
 			     const union bpf_attr *kattr,
 			     union bpf_attr __user *uattr);
+int bpf_prog_test_run_sk_lookup(struct bpf_prog *prog,
+				const union bpf_attr *kattr,
+				union bpf_attr __user *uattr);
 bool btf_ctx_access(int off, int size, enum bpf_access_type type,
 		    const struct bpf_prog *prog,
 		    struct bpf_insn_access_aux *info);
@@ -1692,6 +1695,13 @@ static inline int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
 	return -ENOTSUPP;
 }
 
+static inline int bpf_prog_test_run_sk_lookup(struct bpf_prog *prog,
+					      const union bpf_attr *kattr,
+					      union bpf_attr __user *uattr)
+{
+	return -ENOTSUPP;
+}
+
 static inline void bpf_map_put(struct bpf_map *map)
 {
 }