On Sat, Jun 20, 2020 at 10:55:10PM -0700, Yonghong Song wrote:
> The helper is used in tracing programs to cast a socket
> pointer to a udp6_sock pointer.
> The return value could be NULL if the casting is illegal.
>
> Signed-off-by: Yonghong Song <yhs@xxxxxx>
> ---
> include/linux/bpf.h | 1 +
> include/uapi/linux/bpf.h | 9 ++++++++-
> kernel/trace/bpf_trace.c | 2 ++
> net/core/filter.c | 22 ++++++++++++++++++++++
> scripts/bpf_helpers_doc.py | 2 ++
> tools/include/uapi/linux/bpf.h | 9 ++++++++-
> 6 files changed, 43 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index b17e682454e5..378b6748a8ec 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -1640,6 +1640,7 @@ extern const struct bpf_func_proto bpf_skc_to_tcp6_sock_proto;
> extern const struct bpf_func_proto bpf_skc_to_tcp_sock_proto;
> extern const struct bpf_func_proto bpf_skc_to_tcp_timewait_sock_proto;
> extern const struct bpf_func_proto bpf_skc_to_tcp_request_sock_proto;
> +extern const struct bpf_func_proto bpf_skc_to_udp6_sock_proto;
>
> const struct bpf_func_proto *bpf_tracing_func_proto(
> enum bpf_func_id func_id, const struct bpf_prog *prog);
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index e256417d94c2..3f4b12c5c563 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -3276,6 +3276,12 @@ union bpf_attr {
> * Dynamically cast a *sk* pointer to a *tcp_request_sock* pointer.
> * Return
> * *sk* if casting is valid, or NULL otherwise.
> + *
> + * struct udp6_sock *bpf_skc_to_udp6_sock(void *sk)
> + * Description
> + * Dynamically cast a *sk* pointer to a *udp6_sock* pointer.
> + * Return
> + * *sk* if casting is valid, or NULL otherwise.
> */
> #define __BPF_FUNC_MAPPER(FN) \
> FN(unspec), \
> @@ -3417,7 +3423,8 @@ union bpf_attr {
> FN(skc_to_tcp6_sock), \
> FN(skc_to_tcp_sock), \
> FN(skc_to_tcp_timewait_sock), \
> - FN(skc_to_tcp_request_sock),
> + FN(skc_to_tcp_request_sock), \
> + FN(skc_to_udp6_sock),
>
> /* integer value in 'imm' field of BPF_CALL instruction selects which helper
> * function eBPF program intends to call
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index de5fbe66e1ca..d10ab16c4a2f 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -1523,6 +1523,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> return &bpf_skc_to_tcp_timewait_sock_proto;
> case BPF_FUNC_skc_to_tcp_request_sock:
> return &bpf_skc_to_tcp_request_sock_proto;
> + case BPF_FUNC_skc_to_udp6_sock:
> + return &bpf_skc_to_udp6_sock_proto;
> #endif
> case BPF_FUNC_seq_printf:
> return prog->expected_attach_type == BPF_TRACE_ITER ?
> diff --git a/net/core/filter.c b/net/core/filter.c
> index d26ce3b5e3d5..4ecdadc4aee9 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -9322,3 +9322,25 @@ const struct bpf_func_proto bpf_skc_to_tcp_request_sock_proto = {
> .check_btf_id = check_arg_btf_id,
> .ret_btf_id = &sock_cast_btf_ids[SOCK_CAST_TCP_REQ_SOCK],
> };
> +
> +BPF_CALL_1(bpf_skc_to_udp6_sock, struct sock *, sk)
> +{
> + /* udp6_sock type is not generated in dwarf and hence btf,
> + * trigger an explicit type generation here.
> + */
> + BTF_TYPE_EMIT(struct udp6_sock);
> + if (sk_fullsock(sk) && sk->sk_protocol == IPPROTO_UDP &&
> + sk->sk_family == AF_INET6)
> + return (unsigned long)sk;
> +
> + return (unsigned long)NULL;
> +}
> +
> +const struct bpf_func_proto bpf_skc_to_udp6_sock_proto = {
> + .func = bpf_skc_to_udp6_sock,
> + .gpl_only = true,
Same gpl_only change is needed.
Acked-by: Martin KaFai Lau <kafai@xxxxxx>
