/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. */ #define KBUILD_MODNAME "foo" #include <uapi/linux/bpf.h> #include <linux/in.h> #include <linux/if_ether.h> #include <linux/if_packet.h> #include <linux/if_vlan.h> #include <linux/ip.h> #include <linux/ipv6.h> #include "bpf_helpers.h" struct bpf_map_def SEC("maps") tx_port = { .type = BPF_MAP_TYPE_DEVMAP, .key_size = sizeof(int), .value_size = sizeof(int), .max_entries = 100, }; /* Count RX packets, as XDP bpf_prog doesn't get direct TX-success * feedback. Redirect TX errors can be caught via a tracepoint. */ struct bpf_map_def SEC("maps") rxcnt = { .type = BPF_MAP_TYPE_PERCPU_ARRAY, .key_size = sizeof(u32), .value_size = sizeof(long), .max_entries = 1, }; static 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_redirect_map") int xdp_redirect_map_prog(struct xdp_md *ctx) { void *data_end = (void *)(long)ctx->data_end; void *data = (void *)(long)ctx->data; struct ethhdr *eth = data; int rc = XDP_DROP; int vport, port = 0, m = 0; long *value; u32 key = 0; u64 nh_off; nh_off = sizeof(*eth); if (data + nh_off > data_end) return rc; /* constant virtual port */ vport = 0; /* count packet in global counter */ value = bpf_map_lookup_elem(&rxcnt, &key); if (value) *value += 1; swap_src_dst_mac(data); /* send packet out physical port */ return bpf_redirect_map(&tx_port, vport, 0); } /* Redirect require an XDP bpf_prog loaded on the TX device */ SEC("xdp_redirect_dummy") int xdp_redirect_dummy_prog(struct xdp_md *ctx) { return XDP_PASS; } char _license[] SEC("license") = "GPL";