1#include <uapi/linux/bpf.h>
2#include "bpf_helpers.h"
3#include <uapi/linux/in.h>
4#include <uapi/linux/if.h>
5#include <uapi/linux/if_ether.h>
6#include <uapi/linux/ip.h>
7#include <uapi/linux/ipv6.h>
8#include <uapi/linux/if_tunnel.h>
9#define IP_MF		0x2000
10#define IP_OFFSET	0x1FFF
11
12struct vlan_hdr {
13	__be16 h_vlan_TCI;
14	__be16 h_vlan_encapsulated_proto;
15};
16
17struct flow_keys {
18	__be32 src;
19	__be32 dst;
20	union {
21		__be32 ports;
22		__be16 port16[2];
23	};
24	__u16 thoff;
25	__u8 ip_proto;
26};
27
28static inline int proto_ports_offset(__u64 proto)
29{
30	switch (proto) {
31	case IPPROTO_TCP:
32	case IPPROTO_UDP:
33	case IPPROTO_DCCP:
34	case IPPROTO_ESP:
35	case IPPROTO_SCTP:
36	case IPPROTO_UDPLITE:
37		return 0;
38	case IPPROTO_AH:
39		return 4;
40	default:
41		return 0;
42	}
43}
44
45static inline int ip_is_fragment(struct __sk_buff *ctx, __u64 nhoff)
46{
47	return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off))
48		& (IP_MF | IP_OFFSET);
49}
50
51static inline __u32 ipv6_addr_hash(struct __sk_buff *ctx, __u64 off)
52{
53	__u64 w0 = load_word(ctx, off);
54	__u64 w1 = load_word(ctx, off + 4);
55	__u64 w2 = load_word(ctx, off + 8);
56	__u64 w3 = load_word(ctx, off + 12);
57
58	return (__u32)(w0 ^ w1 ^ w2 ^ w3);
59}
60
61static inline __u64 parse_ip(struct __sk_buff *skb, __u64 nhoff, __u64 *ip_proto,
62			     struct flow_keys *flow)
63{
64	__u64 verlen;
65
66	if (unlikely(ip_is_fragment(skb, nhoff)))
67		*ip_proto = 0;
68	else
69		*ip_proto = load_byte(skb, nhoff + offsetof(struct iphdr, protocol));
70
71	if (*ip_proto != IPPROTO_GRE) {
72		flow->src = load_word(skb, nhoff + offsetof(struct iphdr, saddr));
73		flow->dst = load_word(skb, nhoff + offsetof(struct iphdr, daddr));
74	}
75
76	verlen = load_byte(skb, nhoff + 0/*offsetof(struct iphdr, ihl)*/);
77	if (likely(verlen == 0x45))
78		nhoff += 20;
79	else
80		nhoff += (verlen & 0xF) << 2;
81
82	return nhoff;
83}
84
85static inline __u64 parse_ipv6(struct __sk_buff *skb, __u64 nhoff, __u64 *ip_proto,
86			       struct flow_keys *flow)
87{
88	*ip_proto = load_byte(skb,
89			      nhoff + offsetof(struct ipv6hdr, nexthdr));
90	flow->src = ipv6_addr_hash(skb,
91				   nhoff + offsetof(struct ipv6hdr, saddr));
92	flow->dst = ipv6_addr_hash(skb,
93				   nhoff + offsetof(struct ipv6hdr, daddr));
94	nhoff += sizeof(struct ipv6hdr);
95
96	return nhoff;
97}
98
99static inline bool flow_dissector(struct __sk_buff *skb, struct flow_keys *flow)
100{
101	__u64 nhoff = ETH_HLEN;
102	__u64 ip_proto;
103	__u64 proto = load_half(skb, 12);
104	int poff;
105
106	if (proto == ETH_P_8021AD) {
107		proto = load_half(skb, nhoff + offsetof(struct vlan_hdr,
108							h_vlan_encapsulated_proto));
109		nhoff += sizeof(struct vlan_hdr);
110	}
111
112	if (proto == ETH_P_8021Q) {
113		proto = load_half(skb, nhoff + offsetof(struct vlan_hdr,
114							h_vlan_encapsulated_proto));
115		nhoff += sizeof(struct vlan_hdr);
116	}
117
118	if (likely(proto == ETH_P_IP))
119		nhoff = parse_ip(skb, nhoff, &ip_proto, flow);
120	else if (proto == ETH_P_IPV6)
121		nhoff = parse_ipv6(skb, nhoff, &ip_proto, flow);
122	else
123		return false;
124
125	switch (ip_proto) {
126	case IPPROTO_GRE: {
127		struct gre_hdr {
128			__be16 flags;
129			__be16 proto;
130		};
131
132		__u64 gre_flags = load_half(skb,
133					    nhoff + offsetof(struct gre_hdr, flags));
134		__u64 gre_proto = load_half(skb,
135					    nhoff + offsetof(struct gre_hdr, proto));
136
137		if (gre_flags & (GRE_VERSION|GRE_ROUTING))
138			break;
139
140		proto = gre_proto;
141		nhoff += 4;
142		if (gre_flags & GRE_CSUM)
143			nhoff += 4;
144		if (gre_flags & GRE_KEY)
145			nhoff += 4;
146		if (gre_flags & GRE_SEQ)
147			nhoff += 4;
148
149		if (proto == ETH_P_8021Q) {
150			proto = load_half(skb,
151					  nhoff + offsetof(struct vlan_hdr,
152							   h_vlan_encapsulated_proto));
153			nhoff += sizeof(struct vlan_hdr);
154		}
155
156		if (proto == ETH_P_IP)
157			nhoff = parse_ip(skb, nhoff, &ip_proto, flow);
158		else if (proto == ETH_P_IPV6)
159			nhoff = parse_ipv6(skb, nhoff, &ip_proto, flow);
160		else
161			return false;
162		break;
163	}
164	case IPPROTO_IPIP:
165		nhoff = parse_ip(skb, nhoff, &ip_proto, flow);
166		break;
167	case IPPROTO_IPV6:
168		nhoff = parse_ipv6(skb, nhoff, &ip_proto, flow);
169		break;
170	default:
171		break;
172	}
173
174	flow->ip_proto = ip_proto;
175	poff = proto_ports_offset(ip_proto);
176	if (poff >= 0) {
177		nhoff += poff;
178		flow->ports = load_word(skb, nhoff);
179	}
180
181	flow->thoff = (__u16) nhoff;
182
183	return true;
184}
185
186struct pair {
187	long packets;
188	long bytes;
189};
190
191struct bpf_map_def SEC("maps") hash_map = {
192	.type = BPF_MAP_TYPE_HASH,
193	.key_size = sizeof(__be32),
194	.value_size = sizeof(struct pair),
195	.max_entries = 1024,
196};
197
198SEC("socket2")
199int bpf_prog2(struct __sk_buff *skb)
200{
201	struct flow_keys flow;
202	struct pair *value;
203	u32 key;
204
205	if (!flow_dissector(skb, &flow))
206		return 0;
207
208	key = flow.dst;
209	value = bpf_map_lookup_elem(&hash_map, &key);
210	if (value) {
211		__sync_fetch_and_add(&value->packets, 1);
212		__sync_fetch_and_add(&value->bytes, skb->len);
213	} else {
214		struct pair val = {1, skb->len};
215
216		bpf_map_update_elem(&hash_map, &key, &val, BPF_ANY);
217	}
218	return 0;
219}
220
221char _license[] SEC("license") = "GPL";
222