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