diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c')
-rw-r--r-- | tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c b/tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c new file mode 100644 index 000000000000..2ff1b596e87e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright Leon Hwang */ + +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> + +#define ERRMSG_LEN 64 + +struct xdp_errmsg { + char msg[ERRMSG_LEN]; +}; + +struct { + __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); + __type(key, int); + __type(value, int); +} xdp_errmsg_pb SEC(".maps"); + +struct xdp_attach_error_ctx { + unsigned long unused; + + /* + * bpf does not support tracepoint __data_loc directly. + * + * Actually, this field is a 32 bit integer whose value encodes + * information on where to find the actual data. The first 2 bytes is + * the size of the data. The last 2 bytes is the offset from the start + * of the tracepoint struct where the data begins. + * -- https://github.com/iovisor/bpftrace/pull/1542 + */ + __u32 msg; // __data_loc char[] msg; +}; + +/* + * Catch the error message at the tracepoint. + */ + +SEC("tp/xdp/bpf_xdp_link_attach_failed") +int tp__xdp__bpf_xdp_link_attach_failed(struct xdp_attach_error_ctx *ctx) +{ + char *msg = (void *)(__u64) ((void *) ctx + (__u16) ctx->msg); + struct xdp_errmsg errmsg = {}; + + bpf_probe_read_kernel_str(&errmsg.msg, ERRMSG_LEN, msg); + bpf_perf_event_output(ctx, &xdp_errmsg_pb, BPF_F_CURRENT_CPU, &errmsg, + ERRMSG_LEN); + return 0; +} + +/* + * Reuse the XDP program in xdp_dummy.c. + */ + +char LICENSE[] SEC("license") = "GPL"; |