cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

xdp1_kern.c (2176B)

      1/* Copyright (c) 2016 PLUMgrid
      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#define KBUILD_MODNAME "foo"
      8#include <uapi/linux/bpf.h>
      9#include <linux/in.h>
     10#include <linux/if_ether.h>
     11#include <linux/if_packet.h>
     12#include <linux/if_vlan.h>
     13#include <linux/ip.h>
     14#include <linux/ipv6.h>
     15#include <bpf/bpf_helpers.h>
     16
     17struct {
     18	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
     19	__type(key, u32);
     20	__type(value, long);
     21	__uint(max_entries, 256);
     22} rxcnt SEC(".maps");
     23
     24static int parse_ipv4(void *data, u64 nh_off, void *data_end)
     25{
     26	struct iphdr *iph = data + nh_off;
     27
     28	if (iph + 1 > data_end)
     29		return 0;
     30	return iph->protocol;
     31}
     32
     33static int parse_ipv6(void *data, u64 nh_off, void *data_end)
     34{
     35	struct ipv6hdr *ip6h = data + nh_off;
     36
     37	if (ip6h + 1 > data_end)
     38		return 0;
     39	return ip6h->nexthdr;
     40}
     41
     42SEC("xdp1")
     43int xdp_prog1(struct xdp_md *ctx)
     44{
     45	void *data_end = (void *)(long)ctx->data_end;
     46	void *data = (void *)(long)ctx->data;
     47	struct ethhdr *eth = data;
     48	int rc = XDP_DROP;
     49	long *value;
     50	u16 h_proto;
     51	u64 nh_off;
     52	u32 ipproto;
     53
     54	nh_off = sizeof(*eth);
     55	if (data + nh_off > data_end)
     56		return rc;
     57
     58	h_proto = eth->h_proto;
     59
     60	/* Handle VLAN tagged packet */
     61	if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
     62		struct vlan_hdr *vhdr;
     63
     64		vhdr = data + nh_off;
     65		nh_off += sizeof(struct vlan_hdr);
     66		if (data + nh_off > data_end)
     67			return rc;
     68		h_proto = vhdr->h_vlan_encapsulated_proto;
     69	}
     70	/* Handle double VLAN tagged packet */
     71	if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
     72		struct vlan_hdr *vhdr;
     73
     74		vhdr = data + nh_off;
     75		nh_off += sizeof(struct vlan_hdr);
     76		if (data + nh_off > data_end)
     77			return rc;
     78		h_proto = vhdr->h_vlan_encapsulated_proto;
     79	}
     80
     81	if (h_proto == htons(ETH_P_IP))
     82		ipproto = parse_ipv4(data, nh_off, data_end);
     83	else if (h_proto == htons(ETH_P_IPV6))
     84		ipproto = parse_ipv6(data, nh_off, data_end);
     85	else
     86		ipproto = 0;
     87
     88	value = bpf_map_lookup_elem(&rxcnt, &ipproto);
     89	if (value)
     90		*value += 1;
     91
     92	return rc;
     93}
     94
     95char _license[] SEC("license") = "GPL";