/* 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 <uapi/linux/if_ether.h> #include <uapi/linux/in.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; __u32 options; }; enum cfg_options_flags { NO_TOUCH = 0x0U, READ_MEM = 0x1U, SWAP_MAC = 0x2U, }; 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, }; static __always_inline void swap_src_dst_mac(void *data) { unsigned short *p = data; unsigned short dst[3]; dst[0] = p[0]; dst[1] = p[1]; dst[2] = p[2]; p[0] = p[3]; p[1] = p[4]; p[2] = p[5]; p[3] = dst[0]; p[4] = dst[1]; p[5] = dst[2]; } 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++; /* Default: Don't touch packet data, only count packets */ if (unlikely(config->options & (READ_MEM|SWAP_MAC))) { struct ethhdr *eth = data; if (eth + 1 > data_end) return XDP_ABORTED; /* Avoid compiler removing this: Drop non 802.3 Ethertypes */ if (ntohs(eth->h_proto) < ETH_P_802_3_MIN) return XDP_ABORTED; /* XDP_TX requires changing MAC-addrs, else HW may drop. * Can also be enabled with --swapmac (for test purposes) */ if (unlikely(config->options & SWAP_MAC)) swap_src_dst_mac(data); } return config->action; } char _license[] SEC("license") = "GPL";