Re: [PATCH bpf-next v3 2/3] libbpf: add low level TC-BPF API
From: Daniel Borkmann <daniel@iogearbox.net>
Date: 2021-04-21 22:59:35
Also in:
bpf
On 4/20/21 9:37 PM, Kumar Kartikeya Dwivedi wrote: [...]
quoted hunk ↗ jump to hunk
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index bec4e6a6e31d..b4ed6a41ea70 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h@@ -16,6 +16,8 @@ #include <stdbool.h> #include <sys/types.h> // for size_t #include <linux/bpf.h> +#include <linux/pkt_sched.h> +#include <linux/tc_act/tc_bpf.h> #include "libbpf_common.h"@@ -775,6 +777,48 @@ LIBBPF_API int bpf_linker__add_file(struct bpf_linker *linker, const char *filen LIBBPF_API int bpf_linker__finalize(struct bpf_linker *linker); LIBBPF_API void bpf_linker__free(struct bpf_linker *linker); +/* Convenience macros for the clsact attach hooks */ +#define BPF_TC_CLSACT_INGRESS TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS) +#define BPF_TC_CLSACT_EGRESS TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_EGRESS)
I would abstract those away into an enum, plus avoid having to pull in
linux/pkt_sched.h and linux/tc_act/tc_bpf.h from main libbpf.h header.
Just add a enum { BPF_TC_DIR_INGRESS, BPF_TC_DIR_EGRESS, } and then the
concrete tc bits (TC_H_MAKE()) can be translated internally.
+struct bpf_tc_opts {
+ size_t sz;Is this set anywhere?
+ __u32 handle; + __u32 class_id;
I'd remove class_id from here as well given in direct-action a BPF prog can set it if needed.
+ __u16 priority; + bool replace; + size_t :0;
What's the rationale for this padding?
+};
+
+#define bpf_tc_opts__last_field replace
+
+/* Acts as a handle for an attached filter */
+struct bpf_tc_attach_id {nit: maybe bpf_tc_ctx
+ __u32 handle;
+ __u16 priority;
+};
+
+struct bpf_tc_info {
+ struct bpf_tc_attach_id id;
+ __u16 protocol;
+ __u32 chain_index;
+ __u32 prog_id;
+ __u8 tag[BPF_TAG_SIZE];
+ __u32 class_id;
+ __u32 bpf_flags;
+ __u32 bpf_flags_gen;Given we do not yet have any setters e.g. for offload, etc, the one thing I'd see useful and crucial initially is prog_id. The protocol, chain_index, and I would also include tag should be dropped. Similarly class_id given my earlier statement, and flags I would extend once this lib API would support offloading progs.
+}; + +/* id is out parameter that will be written to, it must not be NULL */ +LIBBPF_API int bpf_tc_attach(int fd, __u32 ifindex, __u32 parent_id, + const struct bpf_tc_opts *opts, + struct bpf_tc_attach_id *id); +LIBBPF_API int bpf_tc_detach(__u32 ifindex, __u32 parent_id, + const struct bpf_tc_attach_id *id); +LIBBPF_API int bpf_tc_get_info(__u32 ifindex, __u32 parent_id, + const struct bpf_tc_attach_id *id, + struct bpf_tc_info *info);
As per above, for parent_id I'd replace with dir enum.
+ #ifdef __cplusplus } /* extern "C" */ #endif