126 lines
2.6 KiB
C
126 lines
2.6 KiB
C
|
/* Copyright (c) 2016 PLUMgrid
|
||
|
|
*
|
||
|
|
* 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.
|
||
|
|
*/
|
||
|
|
#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/bpf_helpers.h>
|
||
|
|
|
||
|
|
struct {
|
||
|
|
__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
|
||
|
|
__type(key, u32);
|
||
|
|
__type(value, long);
|
||
|
|
__uint(max_entries, 256);
|
||
|
|
} rxcnt SEC(".maps");
|
||
|
|
|
||
|
|
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];
|
||
|
|
}
|
||
|
|
|
||
|
|
static int parse_ipv4(void *data, u64 nh_off, void *data_end)
|
||
|
|
{
|
||
|
|
struct iphdr *iph = data + nh_off;
|
||
|
|
|
||
|
|
if (iph + 1 > data_end)
|
||
|
|
return 0;
|
||
|
|
return iph->protocol;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int parse_ipv6(void *data, u64 nh_off, void *data_end)
|
||
|
|
{
|
||
|
|
struct ipv6hdr *ip6h = data + nh_off;
|
||
|
|
|
||
|
|
if (ip6h + 1 > data_end)
|
||
|
|
return 0;
|
||
|
|
return ip6h->nexthdr;
|
||
|
|
}
|
||
|
|
|
||
|
|
#define XDPBUFSIZE 60
|
||
|
|
SEC("xdp.frags")
|
||
|
|
int xdp_prog1(struct xdp_md *ctx)
|
||
|
|
{
|
||
|
|
__u8 pkt[XDPBUFSIZE] = {};
|
||
|
|
void *data_end = &pkt[XDPBUFSIZE-1];
|
||
|
|
void *data = pkt;
|
||
|
|
struct ethhdr *eth = data;
|
||
|
|
int rc = XDP_DROP;
|
||
|
|
long *value;
|
||
|
|
u16 h_proto;
|
||
|
|
u64 nh_off;
|
||
|
|
u32 ipproto;
|
||
|
|
|
||
|
|
if (bpf_xdp_load_bytes(ctx, 0, pkt, sizeof(pkt)))
|
||
|
|
return rc;
|
||
|
|
|
||
|
|
nh_off = sizeof(*eth);
|
||
|
|
if (data + nh_off > data_end)
|
||
|
|
return rc;
|
||
|
|
|
||
|
|
h_proto = eth->h_proto;
|
||
|
|
|
||
|
|
/* Handle VLAN tagged packet */
|
||
|
|
if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
|
||
|
|
struct vlan_hdr *vhdr;
|
||
|
|
|
||
|
|
vhdr = data + nh_off;
|
||
|
|
nh_off += sizeof(struct vlan_hdr);
|
||
|
|
if (data + nh_off > data_end)
|
||
|
|
return rc;
|
||
|
|
h_proto = vhdr->h_vlan_encapsulated_proto;
|
||
|
|
}
|
||
|
|
/* Handle double VLAN tagged packet */
|
||
|
|
if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
|
||
|
|
struct vlan_hdr *vhdr;
|
||
|
|
|
||
|
|
vhdr = data + nh_off;
|
||
|
|
nh_off += sizeof(struct vlan_hdr);
|
||
|
|
if (data + nh_off > data_end)
|
||
|
|
return rc;
|
||
|
|
h_proto = vhdr->h_vlan_encapsulated_proto;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (h_proto == htons(ETH_P_IP))
|
||
|
|
ipproto = parse_ipv4(data, nh_off, data_end);
|
||
|
|
else if (h_proto == htons(ETH_P_IPV6))
|
||
|
|
ipproto = parse_ipv6(data, nh_off, data_end);
|
||
|
|
else
|
||
|
|
ipproto = 0;
|
||
|
|
|
||
|
|
value = bpf_map_lookup_elem(&rxcnt, &ipproto);
|
||
|
|
if (value)
|
||
|
|
*value += 1;
|
||
|
|
|
||
|
|
if (ipproto == IPPROTO_UDP) {
|
||
|
|
swap_src_dst_mac(data);
|
||
|
|
|
||
|
|
if (bpf_xdp_store_bytes(ctx, 0, pkt, sizeof(pkt)))
|
||
|
|
return rc;
|
||
|
|
|
||
|
|
rc = XDP_TX;
|
||
|
|
}
|
||
|
|
|
||
|
|
return rc;
|
||
|
|
}
|
||
|
|
|
||
|
|
char _license[] SEC("license") = "GPL";
|