cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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xdp_redirect_map.bpf.c (2480B)

      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 char 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	struct ethhdr *eth = data;
     77	u64 nh_off;
     78
     79	nh_off = sizeof(*eth);
     80	if (data + nh_off > data_end)
     81		return XDP_DROP;
     82
     83	__builtin_memcpy(eth->h_source, (const char *)tx_mac_addr, ETH_ALEN);
     84
     85	return XDP_PASS;
     86}
     87
     88/* Redirect require an XDP bpf_prog loaded on the TX device */
     89SEC("xdp")
     90int xdp_redirect_dummy_prog(struct xdp_md *ctx)
     91{
     92	return XDP_PASS;
     93}
     94
     95char _license[] SEC("license") = "GPL";