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Diffstat (limited to 'samples/bpf/xdp_rxq_info_kern.c')
-rw-r--r--samples/bpf/xdp_rxq_info_kern.c96
1 files changed, 96 insertions, 0 deletions
diff --git a/samples/bpf/xdp_rxq_info_kern.c b/samples/bpf/xdp_rxq_info_kern.c
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+++ b/samples/bpf/xdp_rxq_info_kern.c
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+/* SPDX-License-Identifier: GPL-2.0
+ * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
+ *
+ * Example howto extract XDP RX-queue info
+ */
+#include <uapi/linux/bpf.h>
+#include "bpf_helpers.h"
+
+/* Config setup from with userspace
+ *
+ * User-side setup ifindex in config_map, to verify that
+ * ctx->ingress_ifindex is correct (against configured ifindex)
+ */
+struct config {
+ __u32 action;
+ int ifindex;
+};
+struct bpf_map_def SEC("maps") config_map = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .key_size = sizeof(int),
+ .value_size = sizeof(struct config),
+ .max_entries = 1,
+};
+
+/* Common stats data record (shared with userspace) */
+struct datarec {
+ __u64 processed;
+ __u64 issue;
+};
+
+struct bpf_map_def SEC("maps") stats_global_map = {
+ .type = BPF_MAP_TYPE_PERCPU_ARRAY,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(struct datarec),
+ .max_entries = 1,
+};
+
+#define MAX_RXQs 64
+
+/* Stats per rx_queue_index (per CPU) */
+struct bpf_map_def SEC("maps") rx_queue_index_map = {
+ .type = BPF_MAP_TYPE_PERCPU_ARRAY,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(struct datarec),
+ .max_entries = MAX_RXQs + 1,
+};
+
+SEC("xdp_prog0")
+int xdp_prognum0(struct xdp_md *ctx)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ void *data = (void *)(long)ctx->data;
+ struct datarec *rec, *rxq_rec;
+ int ingress_ifindex;
+ struct config *config;
+ u32 key = 0;
+
+ /* Global stats record */
+ rec = bpf_map_lookup_elem(&stats_global_map, &key);
+ if (!rec)
+ return XDP_ABORTED;
+ rec->processed++;
+
+ /* Accessing ctx->ingress_ifindex, cause BPF to rewrite BPF
+ * instructions inside kernel to access xdp_rxq->dev->ifindex
+ */
+ ingress_ifindex = ctx->ingress_ifindex;
+
+ config = bpf_map_lookup_elem(&config_map, &key);
+ if (!config)
+ return XDP_ABORTED;
+
+ /* Simple test: check ctx provided ifindex is as expected */
+ if (ingress_ifindex != config->ifindex) {
+ /* count this error case */
+ rec->issue++;
+ return XDP_ABORTED;
+ }
+
+ /* Update stats per rx_queue_index. Handle if rx_queue_index
+ * is larger than stats map can contain info for.
+ */
+ key = ctx->rx_queue_index;
+ if (key >= MAX_RXQs)
+ key = MAX_RXQs;
+ rxq_rec = bpf_map_lookup_elem(&rx_queue_index_map, &key);
+ if (!rxq_rec)
+ return XDP_ABORTED;
+ rxq_rec->processed++;
+ if (key == MAX_RXQs)
+ rxq_rec->issue++;
+
+ return config->action;
+}
+
+char _license[] SEC("license") = "GPL";