This is done to later reuse these in a way that can be shared
among multiple samples.
We are using xdp_redirect_cpu_kern.c as a base to build further support on
top (mostly adding a few other things missing that xdp_monitor does in
subsequent patches).
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
---
samples/bpf/xdp_sample_kern.h | 220 ++++++++++++++++++++++++++++++++++
1 file changed, 220 insertions(+)
create mode 100644 samples/bpf/xdp_sample_kern.h
diff --git a/samples/bpf/xdp_sample_kern.h b/samples/bpf/xdp_sample_kern.h
new file mode 100644
index 000000000000..bb809542ac20
--- /dev/null
+++ b/samples/bpf/xdp_sample_kern.h
@@ -0,0 +1,220 @@
+// SPDX-License-Identifier: GPL-2.0
+/* GPLv2, Copyright(c) 2017 Jesper Dangaard Brouer, Red Hat, Inc. */
+#pragma once
+
+#include <uapi/linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+#define MAX_CPUS 64
+
+/* Common stats data record to keep userspace more simple */
+struct datarec {
+ __u64 processed;
+ __u64 dropped;
+ __u64 issue;
+ __u64 xdp_pass;
+ __u64 xdp_drop;
+ __u64 xdp_redirect;
+};
+
+/* Count RX packets, as XDP bpf_prog doesn't get direct TX-success
+ * feedback. Redirect TX errors can be caught via a tracepoint.
+ */
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+ __type(key, u32);
+ __type(value, struct datarec);
+ __uint(max_entries, 1);
+} rx_cnt SEC(".maps");
+
+/* Used by trace point */
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+ __type(key, u32);
+ __type(value, struct datarec);
+ __uint(max_entries, 2);
+ /* TODO: have entries for all possible errno's */
+} redirect_err_cnt SEC(".maps");
+
+/* Used by trace point */
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+ __type(key, u32);
+ __type(value, struct datarec);
+ __uint(max_entries, MAX_CPUS);
+} cpumap_enqueue_cnt SEC(".maps");
+
+/* Used by trace point */
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+ __type(key, u32);
+ __type(value, struct datarec);
+ __uint(max_entries, 1);
+} cpumap_kthread_cnt SEC(".maps");
+
+/* Used by trace point */
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+ __type(key, u32);
+ __type(value, struct datarec);
+ __uint(max_entries, 1);
+} exception_cnt SEC(".maps");
+
+/*** Trace point code ***/
+
+/* Tracepoint format: /sys/kernel/debug/tracing/events/xdp/xdp_redirect/format
+ * Code in: kernel/include/trace/events/xdp.h
+ */
+struct xdp_redirect_ctx {
+ u64 __pad; // First 8 bytes are not accessible by bpf code
+ int prog_id; // offset:8; size:4; signed:1;
+ u32 act; // offset:12 size:4; signed:0;
+ int ifindex; // offset:16 size:4; signed:1;
+ int err; // offset:20 size:4; signed:1;
+ int to_ifindex; // offset:24 size:4; signed:1;
+ u32 map_id; // offset:28 size:4; signed:0;
+ int map_index; // offset:32 size:4; signed:1;
+}; // offset:36
+
+enum {
+ XDP_REDIRECT_SUCCESS = 0,
+ XDP_REDIRECT_ERROR = 1
+};
+
+static __always_inline
+int xdp_redirect_collect_stat(struct xdp_redirect_ctx *ctx)
+{
+ u32 key = XDP_REDIRECT_ERROR;
+ struct datarec *rec;
+ int err = ctx->err;
+
+ if (!err)
+ key = XDP_REDIRECT_SUCCESS;
+
+ rec = bpf_map_lookup_elem(&redirect_err_cnt, &key);
+ if (!rec)
+ return 0;
+ rec->dropped += 1;
+
+ return 0; /* Indicate event was filtered (no further processing)*/
+ /*
+ * Returning 1 here would allow e.g. a perf-record tracepoint
+ * to see and record these events, but it doesn't work well
+ * in-practice as stopping perf-record also unload this
+ * bpf_prog. Plus, there is additional overhead of doing so.
+ */
+}
+
+SEC("tracepoint/xdp/xdp_redirect_err")
+int trace_xdp_redirect_err(struct xdp_redirect_ctx *ctx)
+{
+ return xdp_redirect_collect_stat(ctx);
+}
+
+SEC("tracepoint/xdp/xdp_redirect_map_err")
+int trace_xdp_redirect_map_err(struct xdp_redirect_ctx *ctx)
+{
+ return xdp_redirect_collect_stat(ctx);
+}
+
+/* Tracepoint format: /sys/kernel/debug/tracing/events/xdp/xdp_exception/format
+ * Code in: kernel/include/trace/events/xdp.h
+ */
+struct xdp_exception_ctx {
+ u64 __pad; // First 8 bytes are not accessible by bpf code
+ int prog_id; // offset:8; size:4; signed:1;
+ u32 act; // offset:12; size:4; signed:0;
+ int ifindex; // offset:16; size:4; signed:1;
+};
+
+SEC("tracepoint/xdp/xdp_exception")
+int trace_xdp_exception(struct xdp_exception_ctx *ctx)
+{
+ struct datarec *rec;
+ u32 key = 0;
+
+ rec = bpf_map_lookup_elem(&exception_cnt, &key);
+ if (!rec)
+ return 1;
+ rec->dropped += 1;
+
+ return 0;
+}
+
+/* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_cpumap_enqueue/format
+ * Code in: kernel/include/trace/events/xdp.h
+ */
+struct cpumap_enqueue_ctx {
+ u64 __pad; // First 8 bytes are not accessible by bpf code
+ int map_id; // offset:8; size:4; signed:1;
+ u32 act; // offset:12; size:4; signed:0;
+ int cpu; // offset:16; size:4; signed:1;
+ unsigned int drops; // offset:20; size:4; signed:0;
+ unsigned int processed; // offset:24; size:4; signed:0;
+ int to_cpu; // offset:28; size:4; signed:1;
+};
+
+SEC("tracepoint/xdp/xdp_cpumap_enqueue")
+int trace_xdp_cpumap_enqueue(struct cpumap_enqueue_ctx *ctx)
+{
+ u32 to_cpu = ctx->to_cpu;
+ struct datarec *rec;
+
+ if (to_cpu >= MAX_CPUS)
+ return 1;
+
+ rec = bpf_map_lookup_elem(&cpumap_enqueue_cnt, &to_cpu);
+ if (!rec)
+ return 0;
+ rec->processed += ctx->processed;
+ rec->dropped += ctx->drops;
+
+ /* Record bulk events, then userspace can calc average bulk size */
+ if (ctx->processed > 0)
+ rec->issue += 1;
+
+ /* Inception: It's possible to detect overload situations, via
+ * this tracepoint. This can be used for creating a feedback
+ * loop to XDP, which can take appropriate actions to mitigate
+ * this overload situation.
+ */
+ return 0;
+}
+
+/* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_cpumap_kthread/format
+ * Code in: kernel/include/trace/events/xdp.h
+ */
+struct cpumap_kthread_ctx {
+ u64 __pad; // First 8 bytes are not accessible
+ int map_id; // offset:8; size:4; signed:1;
+ u32 act; // offset:12; size:4; signed:0;
+ int cpu; // offset:16; size:4; signed:1;
+ unsigned int drops; // offset:20; size:4; signed:0;
+ unsigned int processed; // offset:24; size:4; signed:0;
+ int sched; // offset:28; size:4; signed:1;
+ unsigned int xdp_pass; // offset:32; size:4; signed:0;
+ unsigned int xdp_drop; // offset:36; size:4; signed:0;
+ unsigned int xdp_redirect; // offset:40; size:4; signed:0;
+};
+
+SEC("tracepoint/xdp/xdp_cpumap_kthread")
+int trace_xdp_cpumap_kthread(struct cpumap_kthread_ctx *ctx)
+{
+ struct datarec *rec;
+ u32 key = 0;
+
+ rec = bpf_map_lookup_elem(&cpumap_kthread_cnt, &key);
+ if (!rec)
+ return 0;
+ rec->processed += ctx->processed;
+ rec->dropped += ctx->drops;
+ rec->xdp_pass += ctx->xdp_pass;
+ rec->xdp_drop += ctx->xdp_drop;
+ rec->xdp_redirect += ctx->xdp_redirect;
+
+ /* Count times kthread yielded CPU via schedule call */
+ if (ctx->sched)
+ rec->issue++;
+
+ return 0;
+}
--
2.31.1
