tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
42#define XDPBUFSIZE 64
43SEC("xdp.frags")
44int xdp_prog1(struct xdp_md *ctx)
45{
46 __u8 pkt[XDPBUFSIZE] = {};
47 void *data_end = &pkt[XDPBUFSIZE-1];
48 void *data = pkt;
49 struct ethhdr *eth = data;
50 int rc = XDP_DROP;
51 long *value;
52 u16 h_proto;
53 u64 nh_off;
54 u32 ipproto;
55
56 if (bpf_xdp_load_bytes(ctx, 0, pkt, sizeof(pkt)))
57 return rc;
58
59 nh_off = sizeof(*eth);
60 if (data + nh_off > data_end)
61 return rc;
62
63 h_proto = eth->h_proto;
64
65 /* Handle VLAN tagged packet */
66 if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
67 struct vlan_hdr *vhdr;
68
69 vhdr = data + nh_off;
70 nh_off += sizeof(struct vlan_hdr);
71 if (data + nh_off > data_end)
72 return rc;
73 h_proto = vhdr->h_vlan_encapsulated_proto;
74 }
75 /* Handle double VLAN tagged packet */
76 if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
77 struct vlan_hdr *vhdr;
78
79 vhdr = data + nh_off;
80 nh_off += sizeof(struct vlan_hdr);
81 if (data + nh_off > data_end)
82 return rc;
83 h_proto = vhdr->h_vlan_encapsulated_proto;
84 }
85
86 if (h_proto == htons(ETH_P_IP))
87 ipproto = parse_ipv4(data, nh_off, data_end);
88 else if (h_proto == htons(ETH_P_IPV6))
89 ipproto = parse_ipv6(data, nh_off, data_end);
90 else
91 ipproto = 0;
92
93 value = bpf_map_lookup_elem(&rxcnt, &ipproto);
94 if (value)
95 *value += 1;
96
97 return rc;
98}
99
100char _license[] SEC("license") = "GPL";