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Diffstat (limited to '')
-rw-r--r-- | src/shared/bpf-compat.h | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/src/shared/bpf-compat.h b/src/shared/bpf-compat.h new file mode 100644 index 0000000..9ccb7d8 --- /dev/null +++ b/src/shared/bpf-compat.h @@ -0,0 +1,54 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +#pragma once + +/* libbpf has been moving quickly. + * They added new symbols in the 0.x versions and shortly after removed + * deprecated symbols in 1.0. + * We only need bpf_map_create and libbpf_probe_bpf_prog_type so we work + * around the incompatibility here by: + * - declaring both symbols, and looking for either depending on the libbpf + * so version we found + * - having helpers that automatically use the appropriate version behind the + * new API for easy cleanup later + * + * The advantage of doing this instead of only looking for the symbols declared at + * compile time is that we can then load either the old or the new symbols at runtime + * regardless of the version we were compiled with */ + + +/* declare the struct for libbpf <= 0.6.0 -- it causes no harm on newer versions */ +struct bpf_map_create_opts; + +/* new symbols available from 0.7.0. + * We need the symbols here: + * - after bpf_map_create_opts struct has been defined for older libbpf + * - before the compat static inline helpers that use them. + * When removing this file move these back to bpf-dlopen.h */ +extern int (*sym_bpf_map_create)(enum bpf_map_type, const char *, __u32, __u32, __u32, const struct bpf_map_create_opts *); +extern int (*sym_libbpf_probe_bpf_prog_type)(enum bpf_prog_type, const void *); + +/* compat symbols removed in libbpf 1.0 */ +extern int (*sym_bpf_create_map)(enum bpf_map_type, int key_size, int value_size, int max_entries, __u32 map_flags); +extern bool (*sym_bpf_probe_prog_type)(enum bpf_prog_type, __u32); + +/* helpers to use the available variant behind new API */ +static inline int compat_bpf_map_create(enum bpf_map_type map_type, + const char *map_name, + __u32 key_size, + __u32 value_size, + __u32 max_entries, + const struct bpf_map_create_opts *opts) { + if (sym_bpf_map_create) + return sym_bpf_map_create(map_type, map_name, key_size, + value_size, max_entries, opts); + + return sym_bpf_create_map(map_type, key_size, value_size, max_entries, + 0 /* opts->map_flags, but opts is always NULL for us so skip build dependency on the type */); +} + +static inline int compat_libbpf_probe_bpf_prog_type(enum bpf_prog_type prog_type, const void *opts) { + if (sym_libbpf_probe_bpf_prog_type) + return sym_libbpf_probe_bpf_prog_type(prog_type, opts); + + return sym_bpf_probe_prog_type(prog_type, 0); +} |