These structures will be used to interact between the fuse bpf calls and normal userspace calls Signed-off-by: Daniel Rosenberg <drosen@xxxxxxxxxx> --- include/linux/bpf_fuse.h | 84 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 include/linux/bpf_fuse.h diff --git a/include/linux/bpf_fuse.h b/include/linux/bpf_fuse.h new file mode 100644 index 000000000000..ce8b1b347496 --- /dev/null +++ b/include/linux/bpf_fuse.h @@ -0,0 +1,84 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright 2022 Google LLC. + */ + +#ifndef _BPF_FUSE_H +#define _BPF_FUSE_H + +#include <linux/types.h> +#include <linux/fuse.h> + +struct fuse_buffer { + void *data; + unsigned size; + unsigned alloc_size; + unsigned max_size; + int flags; +}; + +/* These flags are used internally to track information about the fuse buffers. + * Fuse sets some of the flags in init. The helper functions sets others, depending on what + * was requested by the bpf program. + */ +// Flags set by FUSE +#define BPF_FUSE_IMMUTABLE (1 << 0) // Buffer may not be written to +#define BPF_FUSE_VARIABLE_SIZE (1 << 1) // Buffer length may be changed (growth requires alloc) +#define BPF_FUSE_MUST_ALLOCATE (1 << 2) // Buffer must be re allocated before allowing writes + +// Flags set by helper function +#define BPF_FUSE_MODIFIED (1 << 3) // The helper function allowed writes to the buffer +#define BPF_FUSE_ALLOCATED (1 << 4) // The helper function allocated the buffer + +/* + * BPF Fuse Args + * + * Used to translate between bpf program parameters and their userspace equivalent calls. + * Variable sized arguments are held in fuse_buffers. To access these, bpf programs must + * use kfuncs to access them as dynptrs. + * + */ + +#define FUSE_MAX_ARGS_IN 3 +#define FUSE_MAX_ARGS_OUT 2 + +struct bpf_fuse_arg { + union { + void *value; + struct fuse_buffer *buffer; + }; + unsigned size; + bool is_buffer; +}; + +struct bpf_fuse_meta_info { + uint64_t nodeid; + uint32_t opcode; + uint32_t error_in; +}; + +struct bpf_fuse_args { + struct bpf_fuse_meta_info info; + uint32_t in_numargs; + uint32_t out_numargs; + uint32_t flags; + struct bpf_fuse_arg in_args[FUSE_MAX_ARGS_IN]; + struct bpf_fuse_arg out_args[FUSE_MAX_ARGS_OUT]; +}; + +// Mirrors for struct fuse_args flags +#define FUSE_BPF_FORCE (1 << 0) +#define FUSE_BPF_OUT_ARGVAR (1 << 6) +#define FUSE_BPF_IS_LOOKUP (1 << 11) + +static inline void *bpf_fuse_arg_value(const struct bpf_fuse_arg *arg) +{ + return arg->is_buffer ? arg->buffer : arg->value; +} + +static inline unsigned bpf_fuse_arg_size(const struct bpf_fuse_arg *arg) +{ + return arg->is_buffer ? arg->buffer->size : arg->size; +} + +#endif /* _BPF_FUSE_H */ -- 2.44.0.478.gd926399ef9-goog