1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
|
/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com
*
* 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.
*/
#include <uapi/linux/bpf.h>
#include <uapi/linux/in.h>
#include <uapi/linux/if.h>
#include <uapi/linux/if_ether.h>
#include <uapi/linux/ip.h>
#include <uapi/linux/ipv6.h>
#include <uapi/linux/if_tunnel.h>
#include <uapi/linux/mpls.h>
#include <bpf/bpf_helpers.h>
#include "bpf_legacy.h"
#define IP_MF 0x2000
#define IP_OFFSET 0x1FFF
#define PROG(F) SEC("socket/"__stringify(F)) int bpf_func_##F
struct {
__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
__uint(key_size, sizeof(u32));
__uint(value_size, sizeof(u32));
__uint(max_entries, 8);
} jmp_table SEC(".maps");
#define PARSE_VLAN 1
#define PARSE_MPLS 2
#define PARSE_IP 3
#define PARSE_IPV6 4
/* protocol dispatch routine.
* It tail-calls next BPF program depending on eth proto
* Note, we could have used:
* bpf_tail_call(skb, &jmp_table, proto);
* but it would need large prog_array
*/
static inline void parse_eth_proto(struct __sk_buff *skb, u32 proto)
{
switch (proto) {
case ETH_P_8021Q:
case ETH_P_8021AD:
bpf_tail_call(skb, &jmp_table, PARSE_VLAN);
break;
case ETH_P_MPLS_UC:
case ETH_P_MPLS_MC:
bpf_tail_call(skb, &jmp_table, PARSE_MPLS);
break;
case ETH_P_IP:
bpf_tail_call(skb, &jmp_table, PARSE_IP);
break;
case ETH_P_IPV6:
bpf_tail_call(skb, &jmp_table, PARSE_IPV6);
break;
}
}
struct vlan_hdr {
__be16 h_vlan_TCI;
__be16 h_vlan_encapsulated_proto;
};
struct flow_key_record {
__be32 src;
__be32 dst;
union {
__be32 ports;
__be16 port16[2];
};
__u32 ip_proto;
};
static inline int ip_is_fragment(struct __sk_buff *ctx, __u64 nhoff)
{
return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off))
& (IP_MF | IP_OFFSET);
}
static inline __u32 ipv6_addr_hash(struct __sk_buff *ctx, __u64 off)
{
__u64 w0 = load_word(ctx, off);
__u64 w1 = load_word(ctx, off + 4);
__u64 w2 = load_word(ctx, off + 8);
__u64 w3 = load_word(ctx, off + 12);
return (__u32)(w0 ^ w1 ^ w2 ^ w3);
}
struct globals {
struct flow_key_record flow;
};
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, __u32);
__type(value, struct globals);
__uint(max_entries, 32);
} percpu_map SEC(".maps");
/* user poor man's per_cpu until native support is ready */
static struct globals *this_cpu_globals(void)
{
u32 key = bpf_get_smp_processor_id();
return bpf_map_lookup_elem(&percpu_map, &key);
}
/* some simple stats for user space consumption */
struct pair {
__u64 packets;
__u64 bytes;
};
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__type(key, struct flow_key_record);
__type(value, struct pair);
__uint(max_entries, 1024);
} hash_map SEC(".maps");
static void update_stats(struct __sk_buff *skb, struct globals *g)
{
struct flow_key_record key = g->flow;
struct pair *value;
value = bpf_map_lookup_elem(&hash_map, &key);
if (value) {
__sync_fetch_and_add(&value->packets, 1);
__sync_fetch_and_add(&value->bytes, skb->len);
} else {
struct pair val = {1, skb->len};
bpf_map_update_elem(&hash_map, &key, &val, BPF_ANY);
}
}
static __always_inline void parse_ip_proto(struct __sk_buff *skb,
struct globals *g, __u32 ip_proto)
{
__u32 nhoff = skb->cb[0];
int poff;
switch (ip_proto) {
case IPPROTO_GRE: {
struct gre_hdr {
__be16 flags;
__be16 proto;
};
__u32 gre_flags = load_half(skb,
nhoff + offsetof(struct gre_hdr, flags));
__u32 gre_proto = load_half(skb,
nhoff + offsetof(struct gre_hdr, proto));
if (gre_flags & (GRE_VERSION|GRE_ROUTING))
break;
nhoff += 4;
if (gre_flags & GRE_CSUM)
nhoff += 4;
if (gre_flags & GRE_KEY)
nhoff += 4;
if (gre_flags & GRE_SEQ)
nhoff += 4;
skb->cb[0] = nhoff;
parse_eth_proto(skb, gre_proto);
break;
}
case IPPROTO_IPIP:
parse_eth_proto(skb, ETH_P_IP);
break;
case IPPROTO_IPV6:
parse_eth_proto(skb, ETH_P_IPV6);
break;
case IPPROTO_TCP:
case IPPROTO_UDP:
g->flow.ports = load_word(skb, nhoff);
case IPPROTO_ICMP:
g->flow.ip_proto = ip_proto;
update_stats(skb, g);
break;
default:
break;
}
}
PROG(PARSE_IP)(struct __sk_buff *skb)
{
struct globals *g = this_cpu_globals();
__u32 nhoff, verlen, ip_proto;
if (!g)
return 0;
nhoff = skb->cb[0];
if (unlikely(ip_is_fragment(skb, nhoff)))
return 0;
ip_proto = load_byte(skb, nhoff + offsetof(struct iphdr, protocol));
if (ip_proto != IPPROTO_GRE) {
g->flow.src = load_word(skb, nhoff + offsetof(struct iphdr, saddr));
g->flow.dst = load_word(skb, nhoff + offsetof(struct iphdr, daddr));
}
verlen = load_byte(skb, nhoff + 0/*offsetof(struct iphdr, ihl)*/);
nhoff += (verlen & 0xF) << 2;
skb->cb[0] = nhoff;
parse_ip_proto(skb, g, ip_proto);
return 0;
}
PROG(PARSE_IPV6)(struct __sk_buff *skb)
{
struct globals *g = this_cpu_globals();
__u32 nhoff, ip_proto;
if (!g)
return 0;
nhoff = skb->cb[0];
ip_proto = load_byte(skb,
nhoff + offsetof(struct ipv6hdr, nexthdr));
g->flow.src = ipv6_addr_hash(skb,
nhoff + offsetof(struct ipv6hdr, saddr));
g->flow.dst = ipv6_addr_hash(skb,
nhoff + offsetof(struct ipv6hdr, daddr));
nhoff += sizeof(struct ipv6hdr);
skb->cb[0] = nhoff;
parse_ip_proto(skb, g, ip_proto);
return 0;
}
PROG(PARSE_VLAN)(struct __sk_buff *skb)
{
__u32 nhoff, proto;
nhoff = skb->cb[0];
proto = load_half(skb, nhoff + offsetof(struct vlan_hdr,
h_vlan_encapsulated_proto));
nhoff += sizeof(struct vlan_hdr);
skb->cb[0] = nhoff;
parse_eth_proto(skb, proto);
return 0;
}
PROG(PARSE_MPLS)(struct __sk_buff *skb)
{
__u32 nhoff, label;
nhoff = skb->cb[0];
label = load_word(skb, nhoff);
nhoff += sizeof(struct mpls_label);
skb->cb[0] = nhoff;
if (label & MPLS_LS_S_MASK) {
__u8 verlen = load_byte(skb, nhoff);
if ((verlen & 0xF0) == 4)
parse_eth_proto(skb, ETH_P_IP);
else
parse_eth_proto(skb, ETH_P_IPV6);
} else {
parse_eth_proto(skb, ETH_P_MPLS_UC);
}
return 0;
}
SEC("socket/0")
int main_prog(struct __sk_buff *skb)
{
__u32 nhoff = ETH_HLEN;
__u32 proto = load_half(skb, 12);
skb->cb[0] = nhoff;
parse_eth_proto(skb, proto);
return 0;
}
char _license[] SEC("license") = "GPL";
|
