141 lines
3.2 KiB
C
141 lines
3.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0
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* Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
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*
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* Example howto extract XDP RX-queue info
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*/
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#include <uapi/linux/bpf.h>
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#include <uapi/linux/if_ether.h>
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#include <uapi/linux/in.h>
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#include <bpf/bpf_helpers.h>
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/* Config setup from with userspace
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*
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* User-side setup ifindex in config_map, to verify that
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* ctx->ingress_ifindex is correct (against configured ifindex)
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*/
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struct config {
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__u32 action;
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int ifindex;
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__u32 options;
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};
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enum cfg_options_flags {
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NO_TOUCH = 0x0U,
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READ_MEM = 0x1U,
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SWAP_MAC = 0x2U,
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};
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__type(key, int);
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__type(value, struct config);
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__uint(max_entries, 1);
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} config_map SEC(".maps");
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/* Common stats data record (shared with userspace) */
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struct datarec {
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__u64 processed;
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__u64 issue;
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};
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struct {
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__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
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__type(key, u32);
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__type(value, struct datarec);
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__uint(max_entries, 1);
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} stats_global_map SEC(".maps");
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#define MAX_RXQs 64
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/* Stats per rx_queue_index (per CPU) */
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struct {
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__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
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__type(key, u32);
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__type(value, struct datarec);
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__uint(max_entries, MAX_RXQs + 1);
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} rx_queue_index_map SEC(".maps");
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static __always_inline
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void swap_src_dst_mac(void *data)
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{
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unsigned short *p = data;
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unsigned short dst[3];
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dst[0] = p[0];
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dst[1] = p[1];
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dst[2] = p[2];
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p[0] = p[3];
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p[1] = p[4];
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p[2] = p[5];
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p[3] = dst[0];
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p[4] = dst[1];
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p[5] = dst[2];
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}
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SEC("xdp_prog0")
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int xdp_prognum0(struct xdp_md *ctx)
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{
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void *data_end = (void *)(long)ctx->data_end;
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void *data = (void *)(long)ctx->data;
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struct datarec *rec, *rxq_rec;
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int ingress_ifindex;
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struct config *config;
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u32 key = 0;
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/* Global stats record */
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rec = bpf_map_lookup_elem(&stats_global_map, &key);
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if (!rec)
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return XDP_ABORTED;
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rec->processed++;
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/* Accessing ctx->ingress_ifindex, cause BPF to rewrite BPF
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* instructions inside kernel to access xdp_rxq->dev->ifindex
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*/
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ingress_ifindex = ctx->ingress_ifindex;
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config = bpf_map_lookup_elem(&config_map, &key);
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if (!config)
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return XDP_ABORTED;
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/* Simple test: check ctx provided ifindex is as expected */
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if (ingress_ifindex != config->ifindex) {
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/* count this error case */
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rec->issue++;
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return XDP_ABORTED;
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}
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/* Update stats per rx_queue_index. Handle if rx_queue_index
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* is larger than stats map can contain info for.
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*/
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key = ctx->rx_queue_index;
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if (key >= MAX_RXQs)
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key = MAX_RXQs;
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rxq_rec = bpf_map_lookup_elem(&rx_queue_index_map, &key);
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if (!rxq_rec)
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return XDP_ABORTED;
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rxq_rec->processed++;
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if (key == MAX_RXQs)
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rxq_rec->issue++;
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/* Default: Don't touch packet data, only count packets */
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if (unlikely(config->options & (READ_MEM|SWAP_MAC))) {
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struct ethhdr *eth = data;
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if (eth + 1 > data_end)
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return XDP_ABORTED;
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/* Avoid compiler removing this: Drop non 802.3 Ethertypes */
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if (ntohs(eth->h_proto) < ETH_P_802_3_MIN)
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return XDP_ABORTED;
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/* XDP_TX requires changing MAC-addrs, else HW may drop.
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* Can also be enabled with --swapmac (for test purposes)
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*/
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if (unlikely(config->options & SWAP_MAC))
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swap_src_dst_mac(data);
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}
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return config->action;
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}
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char _license[] SEC("license") = "GPL";
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