| Message ID | 20201119162654.2410685-2-revest@chromium.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2,1/5] net: Remove the err argument from sock_from_file | expand |
On Thu, Nov 19, 2020 at 5:27 PM Florent Revest <revest@chromium.org> wrote: > > From: Florent Revest <revest@google.com> > > While eBPF programs can check whether a file is a socket by file->f_op > == &socket_file_ops, they cannot convert the void private_data pointer > to a struct socket BTF pointer. In order to do this a new helper > wrapping sock_from_file is added. > > This is useful to tracing programs but also other program types > inheriting this set of helpers such as iterators or LSM programs. > > Signed-off-by: Florent Revest <revest@google.com> Acked-by: KP Singh <kpsingh@google.com> Some minor comments. > --- > include/uapi/linux/bpf.h | 7 +++++++ > kernel/trace/bpf_trace.c | 20 ++++++++++++++++++++ > scripts/bpf_helpers_doc.py | 4 ++++ > tools/include/uapi/linux/bpf.h | 7 +++++++ > 4 files changed, 38 insertions(+) > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > index 162999b12790..7d598f161dc0 100644 > --- a/include/uapi/linux/bpf.h > +++ b/include/uapi/linux/bpf.h > @@ -3787,6 +3787,12 @@ union bpf_attr { > * *ARG_PTR_TO_BTF_ID* of type *task_struct*. > * Return > * Pointer to the current task. > + * > + * struct socket *bpf_sock_from_file(struct file *file) > + * Description > + * If the given file contains a socket, returns the associated socket. "If the given file is a socket" or "represents a socket" would fit better here. > + * Return > + * A pointer to a struct socket on success or NULL on failure. NULL if the file is not a socket.
On Thu, Nov 19, 2020 at 05:26:51PM +0100, Florent Revest wrote: > From: Florent Revest <revest@google.com> > > While eBPF programs can check whether a file is a socket by file->f_op > == &socket_file_ops, they cannot convert the void private_data pointer > to a struct socket BTF pointer. In order to do this a new helper > wrapping sock_from_file is added. > > This is useful to tracing programs but also other program types > inheriting this set of helpers such as iterators or LSM programs. Acked-by: Martin KaFai Lau <kafai@fb.com>
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 162999b12790..7d598f161dc0 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3787,6 +3787,12 @@ union bpf_attr { * *ARG_PTR_TO_BTF_ID* of type *task_struct*. * Return * Pointer to the current task. + * + * struct socket *bpf_sock_from_file(struct file *file) + * Description + * If the given file contains a socket, returns the associated socket. + * Return + * A pointer to a struct socket on success or NULL on failure. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3948,6 +3954,7 @@ union bpf_attr { FN(task_storage_get), \ FN(task_storage_delete), \ FN(get_current_task_btf), \ + FN(sock_from_file), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 02986c7b90eb..d87ca6f93c58 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1260,6 +1260,24 @@ const struct bpf_func_proto bpf_snprintf_btf_proto = { .arg5_type = ARG_ANYTHING, }; +BPF_CALL_1(bpf_sock_from_file, struct file *, file) +{ + return (unsigned long) sock_from_file(file); +} + +BTF_ID_LIST(bpf_sock_from_file_btf_ids) +BTF_ID(struct, socket) +BTF_ID(struct, file) + +static const struct bpf_func_proto bpf_sock_from_file_proto = { + .func = bpf_sock_from_file, + .gpl_only = false, + .ret_type = RET_PTR_TO_BTF_ID_OR_NULL, + .ret_btf_id = &bpf_sock_from_file_btf_ids[0], + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_btf_id = &bpf_sock_from_file_btf_ids[1], +}; + const struct bpf_func_proto * bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { @@ -1354,6 +1372,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_per_cpu_ptr_proto; case BPF_FUNC_bpf_this_cpu_ptr: return &bpf_this_cpu_ptr_proto; + case BPF_FUNC_sock_from_file: + return &bpf_sock_from_file_proto; default: return NULL; } diff --git a/scripts/bpf_helpers_doc.py b/scripts/bpf_helpers_doc.py index 31484377b8b1..d609f20e8360 100755 --- a/scripts/bpf_helpers_doc.py +++ b/scripts/bpf_helpers_doc.py @@ -435,6 +435,8 @@ class PrinterHelpers(Printer): 'struct xdp_md', 'struct path', 'struct btf_ptr', + 'struct socket', + 'struct file', ] known_types = { '...', @@ -478,6 +480,8 @@ class PrinterHelpers(Printer): 'struct task_struct', 'struct path', 'struct btf_ptr', + 'struct socket', + 'struct file', } mapped_types = { 'u8': '__u8', diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 162999b12790..7d598f161dc0 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -3787,6 +3787,12 @@ union bpf_attr { * *ARG_PTR_TO_BTF_ID* of type *task_struct*. * Return * Pointer to the current task. + * + * struct socket *bpf_sock_from_file(struct file *file) + * Description + * If the given file contains a socket, returns the associated socket. + * Return + * A pointer to a struct socket on success or NULL on failure. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3948,6 +3954,7 @@ union bpf_attr { FN(task_storage_get), \ FN(task_storage_delete), \ FN(get_current_task_btf), \ + FN(sock_from_file), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper