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linux/tools/testing/selftests/bpf/bpf_kfuncs.h

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selftests/bpf: tests for using dynptrs to parse skb and xdp buffers Test skb and xdp dynptr functionality in the following ways: 1) progs/test_cls_redirect_dynptr.c * Rewrite "progs/test_cls_redirect.c" test to use dynptrs to parse skb data * This is a great example of how dynptrs can be used to simplify a lot of the parsing logic for non-statically known values. When measuring the user + system time between the original version vs. using dynptrs, and averaging the time for 10 runs (using "time ./test_progs -t cls_redirect"): original version: 0.092 sec with dynptrs: 0.078 sec 2) progs/test_xdp_dynptr.c * Rewrite "progs/test_xdp.c" test to use dynptrs to parse xdp data When measuring the user + system time between the original version vs. using dynptrs, and averaging the time for 10 runs (using "time ./test_progs -t xdp_attach"): original version: 0.118 sec with dynptrs: 0.094 sec 3) progs/test_l4lb_noinline_dynptr.c * Rewrite "progs/test_l4lb_noinline.c" test to use dynptrs to parse skb data When measuring the user + system time between the original version vs. using dynptrs, and averaging the time for 10 runs (using "time ./test_progs -t l4lb_all"): original version: 0.062 sec with dynptrs: 0.081 sec For number of processed verifier instructions: original version: 6268 insns with dynptrs: 2588 insns 4) progs/test_parse_tcp_hdr_opt_dynptr.c * Add sample code for parsing tcp hdr opt lookup using dynptrs. This logic is lifted from a real-world use case of packet parsing in katran [0], a layer 4 load balancer. The original version "progs/test_parse_tcp_hdr_opt.c" (not using dynptrs) is included here as well, for comparison. When measuring the user + system time between the original version vs. using dynptrs, and averaging the time for 10 runs (using "time ./test_progs -t parse_tcp_hdr_opt"): original version: 0.031 sec with dynptrs: 0.045 sec 5) progs/dynptr_success.c * Add test case "test_skb_readonly" for testing attempts at writes on a prog type with read-only skb ctx. * Add "test_dynptr_skb_data" for testing that bpf_dynptr_data isn't supported for skb progs. 6) progs/dynptr_fail.c * Add test cases "skb_invalid_data_slice{1,2,3,4}" and "xdp_invalid_data_slice{1,2}" for testing that helpers that modify the underlying packet buffer automatically invalidate the associated data slice. * Add test cases "skb_invalid_ctx" and "xdp_invalid_ctx" for testing that prog types that do not support bpf_dynptr_from_skb/xdp don't have access to the API. * Add test case "dynptr_slice_var_len{1,2}" for testing that variable-sized len can't be passed in to bpf_dynptr_slice * Add test case "skb_invalid_slice_write" for testing that writes to a read-only data slice are rejected by the verifier. * Add test case "data_slice_out_of_bounds_skb" for testing that writes to an area outside the slice are rejected. * Add test case "invalid_slice_rdwr_rdonly" for testing that prog types that don't allow writes to packet data don't accept any calls to bpf_dynptr_slice_rdwr. [0] https://github.com/facebookincubator/katran/blob/main/katran/lib/bpf/pckt_parsing.h Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230301154953.641654-11-joannelkoong@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-01 07:49:53 -08:00
#ifndef __BPF_KFUNCS__
#define __BPF_KFUNCS__
/* Description
* Initializes an skb-type dynptr
* Returns
* Error code
*/
extern int bpf_dynptr_from_skb(struct __sk_buff *skb, __u64 flags,
struct bpf_dynptr *ptr__uninit) __ksym;
/* Description
* Initializes an xdp-type dynptr
* Returns
* Error code
*/
extern int bpf_dynptr_from_xdp(struct xdp_md *xdp, __u64 flags,
struct bpf_dynptr *ptr__uninit) __ksym;
/* Description
* Obtain a read-only pointer to the dynptr's data
* Returns
* Either a direct pointer to the dynptr data or a pointer to the user-provided
* buffer if unable to obtain a direct pointer
*/
extern void *bpf_dynptr_slice(const struct bpf_dynptr *ptr, __u32 offset,
void *buffer, __u32 buffer__szk) __ksym;
/* Description
* Obtain a read-write pointer to the dynptr's data
* Returns
* Either a direct pointer to the dynptr data or a pointer to the user-provided
* buffer if unable to obtain a direct pointer
*/
extern void *bpf_dynptr_slice_rdwr(const struct bpf_dynptr *ptr, __u32 offset,
void *buffer, __u32 buffer__szk) __ksym;
#endif
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