1/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
 2 *
 3 * This program is free software; you can redistribute it and/or
 4 * modify it under the terms of version 2 of the GNU General Public
 5 * License as published by the Free Software Foundation.
 6 *
 7 * This program is distributed in the hope that it will be useful, but
 8 * WITHOUT ANY WARRANTY; without even the implied warranty of
 9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
10 * General Public License for more details.
11 */
12#define KBUILD_MODNAME "foo"
13
14#include "vmlinux.h"
15#include "xdp_sample.bpf.h"
16#include "xdp_sample_shared.h"
17
18/* The 2nd xdp prog on egress does not support skb mode, so we define two
19 * maps, tx_port_general and tx_port_native.
20 */
21struct {
22	__uint(type, BPF_MAP_TYPE_DEVMAP);
23	__uint(key_size, sizeof(int));
24	__uint(value_size, sizeof(int));
25	__uint(max_entries, 1);
26} tx_port_general SEC(".maps");
27
28struct {
29	__uint(type, BPF_MAP_TYPE_DEVMAP);
30	__uint(key_size, sizeof(int));
31	__uint(value_size, sizeof(struct bpf_devmap_val));
32	__uint(max_entries, 1);
33} tx_port_native SEC(".maps");
34
35/* store egress interface mac address */
36const volatile __u8 tx_mac_addr[ETH_ALEN];
37
38static __always_inline int xdp_redirect_map(struct xdp_md *ctx, void *redirect_map)
39{
40	void *data_end = (void *)(long)ctx->data_end;
41	void *data = (void *)(long)ctx->data;
42	u32 key = bpf_get_smp_processor_id();
43	struct ethhdr *eth = data;
44	struct datarec *rec;
45	u64 nh_off;
46
47	nh_off = sizeof(*eth);
48	if (data + nh_off > data_end)
49		return XDP_DROP;
50
51	rec = bpf_map_lookup_elem(&rx_cnt, &key);
52	if (!rec)
53		return XDP_PASS;
54	NO_TEAR_INC(rec->processed);
55	swap_src_dst_mac(data);
56	return bpf_redirect_map(redirect_map, 0, 0);
57}
58
59SEC("xdp")
60int xdp_redirect_map_general(struct xdp_md *ctx)
61{
62	return xdp_redirect_map(ctx, &tx_port_general);
63}
64
65SEC("xdp")
66int xdp_redirect_map_native(struct xdp_md *ctx)
67{
68	return xdp_redirect_map(ctx, &tx_port_native);
69}
70
71SEC("xdp/devmap")
72int xdp_redirect_map_egress(struct xdp_md *ctx)
73{
74	void *data_end = (void *)(long)ctx->data_end;
75	void *data = (void *)(long)ctx->data;
76	u8 *mac_addr = (u8 *) tx_mac_addr;
77	struct ethhdr *eth = data;
78	u64 nh_off;
79
80	nh_off = sizeof(*eth);
81	if (data + nh_off > data_end)
82		return XDP_DROP;
83
84	barrier_var(mac_addr); /* prevent optimizing out memcpy */
85	__builtin_memcpy(eth->h_source, mac_addr, ETH_ALEN);
86
87	return XDP_PASS;
88}
89
90/* Redirect require an XDP bpf_prog loaded on the TX device */
91SEC("xdp")
92int xdp_redirect_dummy_prog(struct xdp_md *ctx)
93{
94	return XDP_PASS;
95}
96
97char _license[] SEC("license") = "GPL";