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
17 struct {
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
parse_ipv4(void * data,u64 nh_off,void * data_end)24 static 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
parse_ipv6(void * data,u64 nh_off,void * data_end)33 static 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 SEC("xdp1")
xdp_prog1(struct xdp_md * ctx)43 int 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
95 char _license[] SEC("license") = "GPL";
96