// SPDX-License-Identifier: GPL-2.0 #include <linux/ptrace.h> #include <linux/version.h> #include <uapi/linux/bpf.h> #include <bpf/bpf_helpers.h> #define SAMPLE_SIZE 64ul struct { __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); __uint(key_size, sizeof(int)); __uint(value_size, sizeof(u32)); } my_map SEC(".maps"); SEC("xdp_sample") int xdp_sample_prog(struct xdp_md *ctx) { void *data_end = (void *)(long)ctx->data_end; void *data = (void *)(long)ctx->data; /* Metadata will be in the perf event before the packet data. */ struct S { u16 cookie; u16 pkt_len; } __packed metadata; if (data < data_end) { /* The XDP perf_event_output handler will use the upper 32 bits * of the flags argument as a number of bytes to include of the * packet payload in the event data. If the size is too big, the * call to bpf_perf_event_output will fail and return -EFAULT. * * See bpf_xdp_event_output in net/core/filter.c. * * The BPF_F_CURRENT_CPU flag means that the event output fd * will be indexed by the CPU number in the event map. */ u64 flags = BPF_F_CURRENT_CPU; u16 sample_size; int ret; metadata.cookie = 0xdead; metadata.pkt_len = (u16)(data_end - data); sample_size = min(metadata.pkt_len, SAMPLE_SIZE); flags |= (u64)sample_size << 32; ret = bpf_perf_event_output(ctx, &my_map, flags, &metadata, sizeof(metadata)); if (ret) bpf_printk("perf_event_output failed: %d\n", ret); } return XDP_PASS; } char _license[] SEC("license") = "GPL"; u32 _version SEC("version") = LINUX_VERSION_CODE;